Installers Manual - Pipelife Ireland

Transcript

January 2009 Check out the New Animated Underfloor Heating Website at: www.qpl.ie/ufh/video index table of contents Quality Plastics Limited 05 Overview 09 Floor Materials 10 Floor Structures – Standard 14 Foreword Background Guarantee and products Screed Concrete Insulation Damp Proof Membrane Screed above sub-floor Thin screed above sub-floor Floor Structure – Pre-cast Slab 05 06 08 10 10 11 13 14 16 18 Screed above pre-cast slab (pre-formed insulation) 18 Screed above pre-cast slab (multi-reflective insulation) 20 Floor Structure – Suspended Timber Floor 22 Suspended timber (dry method) 22 Suspended timber (wet method) 24 Floor Finishes 26 Installation procedure of Pipe work 29 Carpet Tile Timber -Hardwood Floor -Moisture Content Installation Damage to pipe Pipe in-transit Proximity to other services Boiler Consideration Boiler pipe work and distribution system Primary / secondary pipe work and distribution system 26 27 27 28 28 29 30 30 30 31 31 31 03 04 index System Components 34 Manifolds • description • location 34 34 34 Mixing valve • 22mm • 28mm 35 35 35 Floor Mixing Unit 36 Pump 36 Typical System Layout 37 System Control 38 Standard Components • Room thermostats • Programmable room thermostats • Wet area probe and sensor • Wiring Centre • Actuators • Time Clock • Heating Control Panel 38 38 38 38 38 39 39 39 Radio Frequency • RF room thermostats • RF Programmable room thermostats • RF Wiring centre and receiver 40 40 40 40 System operation and guidelines Suggested cable sizes Time control and temperature setback 41 41 41 System Commissioning Filling Flow meter adjustment Flow meter cleaning System set up System start up System water treatment Maintenance Guidelines for Homeowners Design Considerations Trouble Shooting Guide Frequently Asked Questions Notes 42 42 42 43 43 43 44 44 44 45 46 47 49 foreword foreword Quality Plastics Limited (QPL) has been in the business of producing quality goods for the Plumbing, Construction and Agricultural sectors for nearly forty years, specialising in the extrusion of polyethylene pipe for these applications. The product range has evolved over this time to the latest generation of Qual-PEX thermoplastic pipes which can carry Hot and Cold Water. Qual-PEX crosslinked polyethylene barrier pipe from QPL is truly a first in this generation of thermoplastic pipes – being the first PEX pipe ever to have been approved to the BS 7291 kitemark and also holding WRc and Irish Agreement Board approvals. In addition, Qual-PEX pipe is fully approved in France and the USA, where it is in widespread use in Underfloor/Radiant Heating systems. As well as being a leading edge manufacturer of pipe for the Plumbing and Heating Industry, QPL has developed a true expertise in the design of heating systems to maximize the potential of Qual-PEX pipe. Many systems are straight-forward and are simply adapted from traditional metal pipe plumbing systems, but new methods of heating buildings are now being opened up with the use of thermoplastic pipe in applications such as wall heating, ceiling heating and most especially Underfloor Heating. QPL has a design team second-to-none specialising in Underfloor Heating systems. These engineers have extensive experience in Heating system design, CAD packages and Building Services which they apply to each individual project to produce a unique system design specification for the client. As this industry grows so does the expertise and the experience of the design team in QPL. This manual has been produced to encapsulate some of the current knowledge and thinking behind the Qual-PEX Underfloor Heating System Design for the benefit of the specifiers and installers of Underfloor Heating Systems. This manual does not purport to address all design, installation and safety considerations associated with the use of Qual-PEX Pipe for Underfloor Heating. It is the responsibility of the user of this manual to determine the viability and safety of each individual application and ensure its compliance with local building regulations. Should more information be required, please contact the first class design team at QPL, who will be more than happy to assist. GARRY D HORGAN CHAIRMAN, QUALITY PLASTICS LTD 05 06 quality plastics ltd. - background Quality Plastics Ltd. - background Quality Plastics Ltd (QPL) was established in 1970 as a pipe extruding company. Over the years the company has gone from strength to strength and now employs over 100 people in both Ireland (Quality Plastics Ltd) and the UK (Qual-Plumb (UK) Ltd). The range of products supplied by QPL is continuing to expand through an ongoing programme of product research and development. One of the many products manufactured by QPL is Qual-PEX cross linked polyethylene barrier pipe, which is used widely for plumbing and heating systems. In addition to the markets in Ireland and the UK, Qual-PEX barrier pipe is also distributed to France, Spain, Norway and the USA. In 1996, the Qual-PEX Underfloor Heating department was set-up and has grown to a work force of 6 dealing with quotations, queries, design and technical support both in-house and on-site. The service provided by this department includes design and supply of the underfloor system (via a Qual-PEX pipe stockist). The key feature of this quality underfloor heating system is Qual-PEX 15mm Barrier pipe, which is BS 7291, Class S approved and carries a 25 year guarantee. Outer Layer of Crosslinked Polyethylene EVOH Oxygen Barrier Layer QUAL-PEX BARRIER PIPE COMPRISES 5 LAYERS: layer -inner and outer layers of crosslinked polyethylene (PEX) - two thin polymer adhesive layers - central EVOH (Ethylene Vinyl Alcohol polymer) barrier Adhesive Layers Inner Layer of Crosslinked Polyethylene Design Service At QPL, the heating engineers design a system to meet the client’s requirements by working in conjunction with them. By entering in the key factors to a specialist software package, QPL’s specialist engineers can determine the heat requirement for each room / zone to produce optimum comfort levels. The QPL underfloor heating department have been working hard implementing constructive changes in line with the QPL continual development plan and have come up with a new combination of materials and controls which will provide a reliable and cost effective control at a very competitive price. In making these changes the design time has been improved and QPL now provides the most technically advanced systems at a very competitive price. The QPL design engineers produce a pipe layout drawing for every individual project showing the configuration of each of the loops and the position of the manifold. A typical pipe layout drawing is shown on the following page. A full design specification is produced detailing the design criteria and guidelines from the initial process of installing the pipe to the commissioning of the system and controls layout. This design is always project specific and each design is tailored to suit the client’s requirements. To obtain a quotation simply forward a good quality set of drawings to Quality Plastics Limited, either directly or via a plumbing contractor / Qual – PEX stockist. QPL Ireland Pipelife UK Depot White’s Cross • Cork• Ireland T: +353-21-4884700 • F: +353-21-4884706 E-mail: [email protected] • Web: www.qpl.ie 13 Saxon Way East • Oakley Hay Industrial Estate • Corby • Northants • NN18 9EY. Tel: 0845 2419 490 • Fax: 0845 2419 491 Email: [email protected] • Web: www.pipelife.co.uk 07 08 guarantee & products guarantee & products Contract Materials: QPL accepts full responsibility for the design of the system and the specification and supply of materials. As an added re-assurance, for the customer, QPL carries professional indemnity insurance to cover all designs. QPL supplies a complete radiant heating system which includes : Distribution manifolds containing supply and return outlets with balancing adjustment and flow meters for each circuit. The responsibility for system installation, commissioning and ultimate system function rests with the Heating Contractor/Installer. Pipe: Underfloor circuits shall be installed using 15mm Qual-PEX barrier cross-linked polyethylene. Qual-PEX is manufactured by QPL and is to be installed in complete accord with manufacturer's instructions. Qual-PEX barrier pipe is manufactured with an internal EVOH oxygen diffusion barrier allowing no more oxygen permeation than 0.1 gram per cubic meter, per day (0.1g/m3/d). Submittals Product Data: Quality Plastics Ltd will provide relevant data for manufactured products and assemblies including installation recommendations and diagrams. Operating and Maintenance Instructions: Includes manufacturer's descriptive literature, operating instructions, maintenance and repair data, and parts description. Warranty Quality Plastics Ltd, provides a twenty-five (25) year manufacturer's warranty for Qual-PEX pipe when used in underfloor heating systems and one (1) year manufacturer's warranty for ancillary components supplied by QPL provided the system has been installed and tested per QPL instructions. Quality assurance General Requirements: Materials shall be delivered in their original, unopened packages to the Qual-PEX stockist. Installer's Qualifications: Installation of Qual-PEX UFH System shall be by a competent installer, ideally approved by Quality Plastics Ltd. Controls: QPL also supply the thermostatic mixing valve and pump required for an UFH system and full system control including digital room thermostat, actuator heads and wiring centres. Pipe Fixing System: QPL also provide various fixing systems to cater for different methods of pipe installation. Primary boiler loop and circulating pump: Primary circulating loop (products) shall be supplied by others with sufficient system water flow to provide boiler supply temperature between 60.0ºC to 82.2ºC with an 11ºC maximum temperature drop between primary loop supply and return piping. Floor Structure: It is the responsibility of the Building Project Manager/ Floor screed Contractor to ensure that all floor structures comply with standard codes of practice and Building regulations. Quality Plastics reserves the right to change components without prior notice. overview overview Modern underfloor heating systems are clean, comfortable, and economical to run, virtually maintenance free and offer tremendous energy saving potential. Conventional heating systems (using convector radiators) provide warmth within a space or building by heating the air in the room. By comparison, UFH transfers heat from a very large surface area, which is only slightly warmer than the room. Floors are warmer and the floor to ceiling temperature and humidity levels remain more constant producing a more comfortable environment for occupants. The heated floor operates at low temperatures and will not cause convection drafts or circulation of dust within the room. The floor surface temperature required is usually quite low and very close to the actual room temperature and always below 29ºC in occupied areas to achieve an acceptable degree of comfort. It is essential however, that floor coverings do not provide too great a degree of insulation or the heat in the UFH system may not be able to raise the room temperature to its design level. The basic operation of a water-based underfloor heating system is pipe embedded within a concrete screed with warm water circulating through the pipe work allowing for the gradual heating of the screed and eventual emitting of heat from the floor into the room. The heat is concentrated where it is most needed for human comfort and energy efficiency. It is quite common to have a mixed system in one building where underfloor heating is used throughout the ground floor and radiators are used in the upper floors / bedroom areas, where only sporadic heat is required. Both systems can be operated off one boiler, but will need different time controls due to the different response times. The only exception to this is where UFH is required for a single room. In this case QPL have a special pump / control unit available which allows a single underfloor heating circuit to be connected to a radiator heating system. The major benefits of a Qual-PEX underfloor heating system are: • Comfortable, even temperature throughout • Efficient on fuel due to lower operating temperatures • Healthier environment with less dust being circulated • Safer—no hot panels or dangerous hard edges • No restrictions on interior design layout • Low maintenance • Maximum usable floor spaces • Excellent value for money 09 10 floor construction materials floor construction materials With any solid floor construction, the following floor materials need to be used and incorporated to construct a solid and effective floor for the laying of any underfloor heating system. Screed A screed is used as a non-structural finish to a concrete floor. It is not a hardwearing finish and must have a floor finish on top of it. The purpose of the screed is to provide a flat level surface. Pre-mixed screed. Pre-mixed screeds have in-built retarders to allow the whole day to lay the screed and fiber re-inforcement, which will increase the strength of the screed. Pumped Screeds These fall into 2 categories Semi-dry Here the pre-mixed semi-dry screed is pumped along a flexible pipe to be discharged into the room - saving the barrowing, and possibility of damage. Very useful if screeding upstairs. Liquid screed Here the screed is pumped in full liquid form making it very easy to move around. It is a quick system to lay, but there is more preparation, to make sure there are no leakage points at the edges. Concrete What is concrete? A mixture of a cement, gravel and sand, gauged with water, which may contain admixtures. How long should it take to set? Dependent on temperature and mix specification 2-4 hours for initial set, 24 for final set depending on the cement type, and the presence of retarders or accelerators; approximately 90% of final strength will be achieved within 28 days. What are the mixes? Typical mix is 1:3:6 of cement, sand, aggregate. The size of aggregate is important - too big and all the voids means more cement is needed, too small and strength reduces. A stronger mix would be 1:2:4 Proportions are by volume not by weight. Additives There are many additives that can be used with Mortar, screed or Concrete, the most useful ones being: Retarder Used to delay the on set of first set by up to 12 hours Rapid Hardener This will bring on the first set in less than an hour; this is useful in frosty weather when you need the first set to happen before frost arrives. A typical screeded floor structure will consist of the following: • Floor finish • Screed or concrete layer • Edge insulation • Underfloor heating pipe • Floor insulation • Floor slab or sub floor floor construction materials 11 Insulation The most important energy saving measure one can make during the design of a new home is to allow for large levels of insulations enclosing the envelope of the building (floors/walls/roof). Insulation is expensive but saves money in the long term. Floor insulation is usually positioned above a layer of hard core and below the concrete slab and floor screed as can be seen below. The insulation required is dictated by Building Regulations (Minimum standards). In recent times these standards have changed several times in an effort to improve the energy efficiency in new dwellings. The most recent change (01-07-08) has improved efficiency by 40 % from previous standards; it is also expected to be further improvement by 20 % in 2010. This improvement of 40 % is a whole building assessment and takes into account building fabric, heating system, and renewable technologies. According to these regulations the maximum floor U-Value required for underfloor heating is 0.15 W/m2K (an improvement from 0.25 W/m2K on previous standards). These regulations only apply to the ground floor. The thickness of insulation required to achieve this combined U-Value will vary depending on the floor structure/area/perimeter and the thermal conductivity of the insulation. For underfloor heating this insulation layer should be placed directly below the screed containing the underfloor pipes and above the hard core and concrete slab as can be seen below. 12 floor construction materials The graph below shows how the insulation thickness varies relative to it’s thermal conductivity and the ratio of the dwellings exposed parameter to its area (P/A). This graph has been compiled assuming a standard slab on ground floor construction with a total U-Value of 0.15 W/m2K. Thickness Available example: A = 150m2 Area Perimeter P = 75 m Thickness available 100 mm Given the P/A ratio and either the thermal conductivity of the insulation or the thickness available for floor insulation the unknown quantity can be determined. The remaining unknown can be determined from the graph Thermal Conductivity example: On average from between 100mm and 120mm of insulation with a thermal conductivity value of 0.022 W/mK will suffice (P/A range between 0.3 – 0.6). Area A = Perimeter P = Thermal conductivity First calculate the P/A ratio P/A = 75/150 = 0.5 Thermal Conductivity = 0.019 W/mK 150 m2 45 m 0.023 W/mK As mentioned previously further improvements will be made to the building regulations in 2010, however Quality Plastics expects the combined U-Value for floors with underfloor heating to remain the same. First calculate the P/A ratio P/A = 45/150 = 0.3 The remaining unknown can be determined from the graph Thickness = 106mm Thermal Conductivity / Thickness Insulation Thickness (mm) 160 140 120 Conductivity = 0.023 W/mK P/A = 0.3 Insulation Thickness ≥ 106 mm 100 80 60 40 20 Insulation Thickness = 100mm P/A = 0.5 Conductivity 0.019 W/mK 0 0.018 0.019 0.02 0.021 0.022 0.023 0.024 0.025 Insulation Thermal Conductivity (W/mK) P/A 0.1 Large House P/A 0.2 P/A 0.3 P/A 0.4 P/A 0.5 P/A 0.6 P/A Ratio P/A 0.7 P/A 0.8 P/A 0.9 P/A 1.0 Small Extension floor construction materials Insulation Installation • • • • The insulation board is simply laid loose over the concrete sub floor. Board joints should be tightly butted, staggered, and laid to a break-bonded pattern. Good practice would be to tape the board joints together to prevent any screed seeping through and “floating” the insulation boards. The floor slab should be uniformly flat without any steps or gaps to provide continuous bearing support to the insulating board. The use of 25mm edge insulation is also recommended. The edge insulation is laid along any external wall and should be of sufficient height to accommodate the total depth of screed to be poured. Edge insulation prevents any heat escaping into the wall and thermal bridging occurring. Reasons for insulation A house that is properly and sufficiently insulated: • Is more energy-efficient, and therefore, saves the homeowner money. • Does not need extra effort and expense to keep it comfortable – insulation is permanent and usually does not require maintenance. • Has warmer floors and temperatures are more uniform throughout the house. Damp Proof membrane When using a damp proof membrane the following points should be adhered to: • • • • The DPM is usually positioned between the hardcore and sub-floor with a sandblind to protect the membrane from damage. Where DPM is laid below concrete, it should be at least 1200 gauge material laid with joints sealed. Avoid sharp projections and damage to the membrane Take care not to damage the DPM at the junction with the wall DPC when power floating the slab. 13 14 floor structures - types floor structures - standard It should be possible to install an underfloor heating system into any normal floor without requiring significant changes to the floor structure. However, there are some basic requirements that need to be adhered to: • • The temperature within the floor structure must not be raised to a level at which the strength and characteristics of the floor are adversely affected. Insulation of adequate thickness and U - value must be provided to limit the downward heat losses from the floor. screed above sub-floor (tile finish) • • The floor finish must have a sufficiently low resistance to the passage of heat to enable the heat to be emitted into the room or space above. Consideration must be given to any other services contained within the floor structure that may be affected by the increased temperature. The three most common type of floor construction are: • Screed above sub-floor • Screed above pre-cast slab • Suspended Timber Floor (joist) where to use floor structures - screed above sub-floor Screed above a Sub-Floor • The hardcore should be well compacted and finished with not less than 25mm of sand to protect the DPM. • This DPM is positioned on top of the sand which combines with the DPC to prevent moisture infiltration. • Next a concrete sub-floor is poured to engineering specifications and allowed to dry. • An insulating layer must be installed below the plane of the pipe. Edge insulation must be installed around the perimeter or external walls up to finished floor level. Edge insulation permits the free expansion of the floor screed. • Insulation boards should conform to current building regulations. On average from between 100mm and 120mm of insulation with a thermal conductivity of 0.022W/mK will suffice (P/A range between 0.3 - 0.6). See page 12 for further details. • The insulation must be laid in a staggered format, any joints taped together to prevent screed slipping into the cracks and care must be taken not to damage the boards during installation. • The rapid rail lengths are laid at 90º to the direction of the pipe and are fixed in position using the red fixing clips. Fixing clips are used at 400mm centers along the length of rapid rail. • The rail is installed at approximately 1000mm intervals and should span the width of the zone. • The rail can be snapped to length when required. • Pipe spacing is easy to maintain using rail as pipe grooves are all 25mm apart. • 60mm green clips are also used to fix the pipe directly to the insulation layer at bends in the loop pattern. • Alternatively, the pipe may be cable tied to a steel mesh laid over the insulation. • A normal floor screed (4:1) sand and cement may be used with underfloor heating. The minimum depth of screed above insulation is 65mm and the practicable maximum is 100mm. Care should be taken that the screed is laid from planking to protect the pipe from damage. If ready mix concrete is being used then it should be mixed with a 10mm pea gravel base. • To ensure the pipe has not been damaged during installation a pressure test of 6-bar must be carried out for one hour. Once successful the pressure is dropped to 3-bar and allowed stand (during the pour) until second fixing. • The finished floor covering should not be fitted until the screed has completely dried out. As a rule of thumb, allow a minimum of 1-week drying time per 25mm screed. 15 16 floor structures - screed above sub-floor thin screed method above sub-floor (solid wood finish) where to use floor structures - screed above sub-floor Solid wood floor above a sub floor using 50mm screed. • Where an underfloor heating system is to be installed below solid wood flooring, special design considerations should be taken into account for the floor structure. The surface of the floor structure should be flat and even. The concrete sub-floor should be set and cured. • 100mm -120mm x 50mm battens should be laid on top of the sub floor at 400mm centers. • 100mm -120mm high-density polyurethane insulation should be cut to fit in-between the battens (see page 12). • The 100mm -120mm x 50mm battens are then counter battened with 50mm x 50mm battens at 400mm centres. These battens should stop short to allow the pipes turn. • Qual-PEX 15mm barrier pipe is fixed between the counter battens at the correct spacing using fixing rail and clips. • To ensure the pipe has not been damaged during installation a pressure test of 6-bar must be carried out for one hour. Once successful the pressure is dropped to 3-bar and allowed stand (during the pour) until second fixing. • A lean mix of 8:1 sand and cement is installed between the counter battens, and finished flush with the top of the battens. • The mix should be just wet enough to react and bond, but dry enough to minimise the additional load on the structure. • The screed is allowed to dry out completely before the finishing floor deck is installed using the battens as fixing points. (allow 1– 2 weeks drying time). 17 18 floor structures - screed above pre-cast slab screed above pre-formed insulation (tile finish) where to use Only to be used in intermediate floors such as apartment developments on pre-cast concrete slabs Heating and Domestic Hot Water Systems for dwellings-Achieving compliance with (TGDL) Part L 2008. Section 7. Underfloor heating systems page 57. “Intermediate floors with heated rooms below, complying with both Part L and Part E of the Regulations, should have a separating layer of system thermal insulation where the minimum thermal resistance is given as not less that R = 0.5 m2 K/W (U-Value of total floor = 1.33W/m2K)” floor structures - screed above pre-cast slab Screed above pre-formed Insulation • The pre-cast slab must be swept clean and be free from dirt and debris before any work is carried out. • Edge insulation must next be installed around the perimeter or external walls up to finished floor level. Edge insulation permits the free expansion of the floor screed. • Place the pre-formed Insulation board down. This board contains “noggins” which hold the underfloor pipe in place. • The insulation must be laid in a staggered format, any joints must be taped together to prevent screed slipping into the cracks and care must be taken not to damage the boards during installation. • Pipe spacing is easy to maintain using pre-formed insulation as pipe grooves are all 200mm apart. • A normal floor screed (4:1) sand and cement may be used with underfloor heating. The minimum depth of screed above insulation is 65mm and the practicable maximum is 100mm. If ready mix concrete is being used then it should be mixed with a 10mm pea gravel base. • To ensure the pipe has not been damaged during installation a pressure test of 6-bar must be carried out for one hour. Once successful the pressure is dropped to 3-bar and allowed stand (during the pour) until second fixing. • The finished floor covering should not be fitted until the screed has completely dried out. As a rule of thumb, allow a minimum of 1-week drying out time per 25mm screed. 19 20 floor structures - screed above pre-cast slab screed above multi-reflective insulation where to use Only to be used in intermediate floors such as apartment developments on pre-cast slabs Heating and Domestic Hot Water Systems for dwellings-Achieving compliance with (TGDL) Part L 2008. Section 7. Underfloor heating systems page 57. “Intermediate floors with heated rooms below, complying with both Part L and Part E of the Regulations, should have a separating layer of system thermal insulation where the minimum thermal resistance is given as not less that R = 0.5 m2 K/W (U-Value of total floor = 1.33W/m2K)” floor structures - screed above pre-cast slab Screed above multi-reflective Insulation • The surface of the slab should be swept clean and free from any debris. • A suitable layer of thin multi-reflective insulation is installed over the whole surface area. • The insulation is turned up at the perimeter to act as edge insulation and separate the screed from the wall. • A steel mesh of grade A 142 or similar is laid on top of the insulation and the Qual-PEX 15mm barrier pipe is fixed to the mesh using cable ties. • To ensure the pipe has not been damaged during installation a pressure test of 6-bar must be carried out for one hour. Once successful the pressure is dropped to 3-bar and allowed stand (during the pour) until second fixing. 21 22 floor structures - suspended timber floor structures - suspended timber Underfloor heating in suspended timber floors Underfloor heating systems may be installed successfully under suspended timber floors provided that the floor is constructed to suit the application. Therefore it is essential that planning begins at an early stage in the project and the building contractor is informed of the construction requirements for the underfloor heating. The main consideration is the additional structural load. There are two main methods of this type of floor construction: • dry method • wet method dry method (diffuser plate method for suspended timber) where to use floor structures - suspended timber (dry) Dry Method (Aluminum Diffuser plates) • This method can be used in projects where the added weight of a thin slab is undesirable. The response time of this type of system is comparable with radiator systems, however good levels of insulation directly beneath the diffuser plates are essential for efficient operation. • Aluminum double plates measuring 1000mm x 400mm are used to spread the heat evenly across the underside of the floor deck. • The insulation required will depend on the floor level. For ground floor level a U-Value of 0.15 W/m2K (see page 12) is required, resulting in between 100mm and 120mm of insulation. For intermediate floor levels the U-value of 1.33 W/m2K (see page 18) is required resulting in only a thin layer being used. • Fix the diffuser plates on one side only of the joist to allow the plates to expand freely when the floor deck is laid on top. • The plates are fabricated to ensure the Qual-PEX pipe is tightly encapsulated only after the deck is laid. • There should be a gap of approximately 15mm - 20mm between the individual plates. • The line of the plates should terminate 300mm from the end wall of the zone to allow the Qual-PEX pipe to be returned at a radius of 200mm. • The joints should be notched at each end of the room to allow access for the under floor pipe. • To ensure the pipe has not been damaged during installation a pressure test of 6-bar must be carried out for one hour. Once successful the pressure is dropped to 3-bar and allowed stand until second fixing. • If required a thin plywood sub-floor is laid above the diffuser plates to allow for the fixing of a floating floor (tile or carpet). 23 24 floor structures - suspended timber (wet) wet method 30mm -50mm screed where to use floor structures - suspended timber (wet) Wet Method • Note that this method of using a biscuit screed (8 : 1 sand and cement) will add considerable weight to the structure, particularly before it dries out. Ensure that your engineer is aware of the added weight on the floor joists so that they may take into account the design of the floor structure. • Attach a set of 50mm x 50mm battens to the side of each joist running the same direction as the joist. • Cut a light layer of 10mm – 15mm plywood to fit on top of these battens to allow a layer of insulation to be fitted. • The insulation required will depend on the floor level. For ground floor level a U-Value of 0.15 W/m2K (see page 12) is required, resulting in between 100mm and 120mm of insulation. For intermediate floor levels the U-value of 1.33 W/m2K (see page 18) is required resulting in only a thin layer being used. • The rapid rail fixing system is now cut and placed between the joist at 1m intervals. • The joist should be notched at each end of the room to allow access for the underfloor pipe. • To ensure the pipe has not been damaged during installation a pressure test of 6-bar must be carried out for one hour. Once successful the pressure is dropped to 3-bar and allowed stand until second fixing. • A lean mix of sand and cement (8:1) is poured between the joist and finished off flush with the top of the joist. The mix should be wet enough to react and bond, but dry enough to minimise the additional load on the structure. • The screed is allowed to dry out completely before the finished floor deck is installed, (allow 1 – 2 weeks drying out time). • If required a thin plywood sub-floor is laid above the diffuser plates to allow for the fixing of a floating floor (tile or carpet). 25 26 floor finishes floor finishes Most floor finishes are able to cope with an UFH system if the underside of the floor is well insulated. However the maximum temperature limits, specified by the floor manufacturer must be checked against the maximum design floor surface temperatures for a given room or space. Some finishes which are considered to be very hard wearing are actually quite temperature sensitive and have similarly low surface temperature limits. Many vinyl tiles and plastic floor coverings fall into this category. Carpet Flooring Most fitted carpets can be good transmitters of heat. It is important however to make sure that the underlay is suitable for UFH and has a low TOG value. The TOG values of carpets and underlays should be available from the respective manufacturers. The TOG rating of an underlay should not exceed 0.5. The maximum TOG value of carpet should be 1.0 – 1.5. Although there are many synthetic types of carpet underlay, only rubber types should be used over underfloor heating systems. Rubber underlays come in two types: slab or waffle. The quality of the rubber is important, the cheaper products use fillers and have oily compounds that can leach out over time when heat is applied resulting in an underlay that will degrade over time. A good quality underlay will usually have a lifetime warranty. Such underlays are generally quite satisfactory with underfloor heating. A typical TOG / R-value chart is shown below: Tog Value Thermal Resistance Typical Examples 0.0 0.0 m2K/W Ceramics, stone, slate, marble 0.5 0.5 m2K/W Synthetic blocks, linoleum, laminates 1.0 0.10 m2K/W Carpets, underlays, 13mm hardwood, parquet 1.5 0.15m2K/W Deep pile carpets, 22mm hardwoods and laminates floor finishes Tiled Floor Ceramic tile floors work well with UFH as they provide minimal resistance to heat. To prevent any cracking occurring it is always advisable to use a suitable tiling adhesive that is specifically designed to work with underfloor heating. Hardwoods (e.g. oak, maple) are a better choice over softwood (e.g. pine) as they have lower resistance values and therefore do not suppress the heat rising from the slab below. Pre-finished floating wood floor systems or floating floors are an excellent alternative to traditional wood flooring, because of simpler floor construction and ease of installation. Where possible use boards narrower than 70mm. The narrower the board the less shrinkage that will occur. If wider boards are desired, lower surface temperatures should be maintained, while ensuring that the resulting lower heat outputs can provide the room heating requirement. The best way to minimise changes in wood moisture content is to ensure that the wood is properly acclimatised to the conditions that it will see in service, and finish the wood floor with a low permeability coating. Timber floorings Underfloor heating installed below a finished wood floor can provide both a comfortable and efficient heating system. However, warming wood flooring can present certain unique design and installation considerations in order to minimise possible shrinkage of the flooring. With few exceptions, the maximum design surface temperature below wood flooring should not exceed 29ºC (always check with the timber manufacturer if this limit is sufficient). 27 28 floor finishes Hardwood Flooring Moisture content Hardwood flooring has many advantages, healthier, easier to clean, but it is expensive and can be prone to scratches. High humidity or moisture levels must be prevented before, during and after a wood floor installation. The concrete floor must be fully cured prior to any wood flooring installation and the heating should be operational for one week prior to the installation. This will help to establish both temperature and moisture at or near occupancy levels. There are 4 main types of hardwood flooring • • • • Solid wood Veneer Laminated construction solid wood Laminate Solid Wood Generally these should be fixed down securely, the neatest way being by setting battens into the screed and then screwing the individual wooden planks to this batten. No air gaps are allowed. Veneer Here the substrate is typically MDF or similar, with a thin veneer of hardwood. These are fully finished and although inexpensive, are unsuitable for areas of heavy wear, as they cannot be re-sanded. Laminated Construction solid wood Consists of floor strips where the base is made of layers of a multi-cross core, topped with a wear layer of expensive hardwood. These wear layers can be up to 7mm thick, which gives the same number of re-sanding operations as a one piece solid wood construction. Generally these are not fixed, and are laid as floating floors. Laminate There are several versions, based on a print or photographic film being stuck onto the surface of a composite board such as MDF. Due to the thinner section, typically around 13mm, they are particularly useful for over underfloor heating. *note:Wood floors expand and shrink according to moisture conditions. The installation of the wood flooring should not proceed until the buildings moisture content is below 10%. The flooring material (approx 8% kiln dried) should be placed in the room in which it is to be installed for a minimum of 2 weeks at conditioned temperature and moisture levels to fully acclimatise it to its environment. If system operation has been used to achieve required room temperature and moisture levels it must be turned off during the flooring installation and temporary heat provided as necessary. The heating system should not be turned on again until the floor staining and sealing materials are fully dried, typically 5 – 7 days. installation procedures for the pipe loops installation procedure for the pipe loops • Start by mounting the manifolds in the chosen location and installing the rapid rail fixing system over the insulating layer. • For each zone refer to the zone list which gives details about pipe circuit lengths and flow rates. Also refer to the pipe cutting list to establish the precise cut to make from each coil of pipe. One end of the pipe coil is connected to the manifold and the installer begins by working towards the zone. • • If possible two people should carry out the installation work, one uncoiling the pipe while the other clips it to the fixing rail or on mesh. Alternatively a pipe un-coiler may be used which allows one man to lay the pipe. The flow pipe is fixed to run around the out side wall at approx 100mm from the perimeter. • The loop is installed according to the custom designed pipe spacing and pattern back to the manifold. • Although the design spacing of the pipes may produce a bend radius which is less than the minimum bend radius recommended for Qual – PEX (6-8 times the pipe diameter) this minimum radius should be maintained by forming a keyhole shape bend where necessary. • On completion of the circuit, the end of the loop is connected to the return port on the manifold, and is clearly labelled. • When all the loops are installed, visually inspect the pipe work for any possible damage that may have occurred during the installation procedure. • To ensure the pipe has not been damaged during installation a pressure test of 6-bar must be carried out for one hour. Once successful the pressure is dropped to 3-bar and allowed stand (during the pour) until second fixing. • This pressure test should be maintained while the screed floor is being poured and should be checked at regular intervals to ensure that no damage has been caused to the pipe loops • *Never leave a pressure test running on an exposed site where there is a risk of freezing conditions. In such circumstances use air or nitrogen gas to pressure test the system. 29 30 installation procedures for the pipe loops Damage to the pipe during installation : Repair If you have damaged the pipe and need to make a repair to it, follow the step by step instructions: • Cut out the damaged section of pipe (approximately 50mm at either side of the damaged pipe). QPL recommends the use of a pipe cutter specifically designed for plastic pipe. • Push the Qual-PEX 15mm support insert into the pipe—it will assist in re-rounding the pipe after the cutting action. The insert will support the pipe in the joint. • Connect the pipe work together using a suitable 15mm compression or push-fit fitting. • Put some fine sand underneath the pipe work to act as bedding. • Wrap the completed fitting in gauze to ensure a tight seal, to prevent the screed from coming in contact with the fitting. • Lay the fitting on the sand and cover with screed. Pipe in transit to other heated areas Such pipe runs deserve special attention, as they rarely form part of the heating to the room through which they pass, and can distort temperature control considerably. For this reason pipes are usually spaced 50mm apart, to give the least floor surface area and are located beside the skirting board for the least impact. It is also recommended to use corrugated ducting and to sleeve every second pipe to reduce the heat output in areas where pipes may be bunched together i.e., to reduce hot spots. Qual-PEX should be sleeved in ducting when passing through walls, expansion joints and where it enters and exits floor screeds. The use of ducting is also recommended to limit thermal expansion in areas where the pipe runs are very close together such as near manifold positions and to prevent excessive hotspots in this area. Ducting may also be used in areas where pipes are running under kitchen units or other fixtures where heat emission is not desired. Proximity of UFH pipe work to other services Modern service systems can include service pipes run in flexible conduits within the insulation layer beneath the floor to travel relatively great distances uninterrupted. It is necessary to ensure that the UFH system does not adversely affect the other services within the dwelling. Where service pipes are run in conduit below an underfloor heating system, protection of cold water pipes is mandatory. Electrical power cables and conduits must also be protected against overheating. Provision shall be made, where necessary to allow for expansion and contraction of the buried pipe eg., where gas pipes are laid close to heating system pipes. Good practice is to lay the gas pipe beneath the underfloor insulation prior to any screed being poured. boiler considerations boiler considerations Boiler noise : boilers with high efficiency usually have a low water content and require a minimum flow rate to be maintained through the heat exchanger to ensure that the heat can be removed quickly enough. Small systems which do not require a high circulator duty, can occasionally cause noise problems if the boiler requirement for a minimum flow rate is overlooked. In such cases, an automatic bypass valve should be fitted so that the minimum water quantity can flow through the boiler without relying on circulation through the radiators. In these circumstances the circulator must be capable of satisfying the duty on both the system and bypass. • After the room by room heat loss calculations has been performed, the first component to be considered is the boiler. The boiler must be sized so that the output is marginally greater than the calculated total heat loss. Auxiliary loads such as domestic hot water, radiators and supplementary heating (towel rail etc) must be considered and added to the boiler load. • Ensure that the boiler is sized to meet the requirements of the highest seasonal loads of the building. • It is recommended that multiple boilers be used in larger systems. This will improve overall efficiency by permitting the shut down of boilers when full heat output is not required. Multiple boilers also provide back-up capacity in case one of the boilers fail. • Boiler efficiency is greatly affected by boiler water temperature. High water temperature increases the opportunity for on cycle and off cycle losses. With high water temperature on cycle losses occur because the heat is transferred from the flue gases to the water. This means that more heat will escape up the chimney. Furthermore, a higher water temperature increases boiler jacket and distribution pipe losses in off-cycle. • Most boiler manufactures specify a minimum return water temperature, flow rate and temperature rise. In a boiler, when fuel is burned, water vapor, carbon dioxide and heat are produced. • If the flue side surface of a cast iron boiler drops below the dew point (45ºC - 50ºC) the low return water temperature will cause water vapor to condense on the surface of the cast iron. Start-up condensation is common and usually presents no problems. However continuous condensation will cause the surface of the boiler to corrode. This will significantly shorten the service life of the boiler. Therefore the system pipe work should be configured to maintain a high back end temperature at all times. In addition to the potential problems of corrosion, low back-end temperatures will significantly reduce the efficiency of the boiler by requiring it to be on for long periods of time to heat the return water back up to the supply water temperature. Primary/Secondary Distribution System There are many different pipe layouts used in central heating systems, but the most practical and efficient piping system for multi-zoned underfloor heating systems is the primary/ secondary system. This type of installation has been standard practice in commercial buildings for many years and offers great versatility in terms of efficient operation, ease of maintenance, controllability, and easy installation. This system will ensure high back end temperatures at all times. The system operates in the following way: • A boiler circulates water around the primary loop whenever the boiler is switched on. The primary pump ensures a continuous and constant flow rate through the boiler irrespective of the overall demand. 31 32 boiler considerations Because the secondary circuits have been connected using closely coupled tees the primary pump will not cause circulation to occur in the secondary circuits (the water will always take the shortest route back to the primary pump inlet). • The secondary circuits are also individually pumped(zone pumps) and the operation of any of these zone pumps will have no effect on the other circuits. All this makes it easy to plan and install the distribution system using domestic size pipe and equipment. • Secondary circuits requiring different water flow temperatures can be linked into the primary loop but it is important to connect the circuits requiring the hottest supply water upstream of the lower temperature circuits. Pipe sizing and layout: • The primary pump will be designed to deliver the sum of all individual flow rates in the secondary zone against the head loss in the primary circuit. • The diameter of the primary pipe work will be (at least) one size larger than the diameter of the secondary connections. All necessary safety equipment will be connected to the primary circuit and the relevant positions of these basic components will ensure that the system operates without any air related problems. The flow and return connections to the secondary circuits will be spaced at a distance of not more that 15cm C/C with a minimum of 20cm of straight pipe upstream and downstream of these connections. Position of Primary pump and Expansion vessel/feed: These components have an important relationship to each other in a well-designed heating system. The connection between expansion vessel and the system piping is the point of no pressure change (neutral point) and its pressure remains constant regardless of whether or not the pump operates. When the neutral point is located close to the suction side of the pump then the pump suction pressure is fixed and the differential pressure will appear as an increase above the static. Therefore the system operates under a positive pressure which provides the best possible condition to eliminate air. The neutral point also provides the best location to connect the make up water for the system as it is the only place in the system where the pump operation does not affect system pressure. A pump fitted on the flow from the boiler provides a point of low solubility between boiler and pump, the optimal location for an air eliminator where all the air will be eliminated to ensure the system will be air free. boiler considerations The figure shows a typical primary/secondary system for an installation with a radiator circuit, a domestic hot water circuit and an underfloor heating circuit. The main advantages of the system are: 1. On/Off control to zones using zone circulators (pumps). 2. Allows independent time and temperature control of different zones. 3. Permanent by-pass circuit ensures continuous flow through the boiler, maintaining a high back-end temperature at the boiler. 4. The relative positions of the circulators and the feed and pressure vessel ensure a positive pressure on the system at all times. This will assist with air elimination and protect the pumps from problems of cavitation. 5. Allows pumps and controls to be located in one area, simplifying installation. 33 34 system components system components Manifolds Quality Plastics manifolds provide the flexibility necessary to design and commission the optimum system for any given project. The pressure drop across the manifold will limit the number of loops a single manifold can serve to a maximum of 12. All manifold distribution headers and accessories are nickel plated.The pre assembled manifold comes complete with : • • • • • • • Lockshield valves with individual flow meters Thermostatically controllable valves with protection caps on the return 2 no. blanking plugs with o-ring sealing gasket 2 no. water drain valves 2 no. bleed valves 2 no. metal brackets 2 no. temperature gauges to observe supply and return water temperatures. Location of Manifold • Locate and mark all different zones on site. To comply with building regulations separate temperature control of living areas and sleeping areas is necessary. This may require the use of separate manifolds. • Decide on all manifold locations. Manifolds may be split to provide better access within the zone area and reduce any piping congestion in front of the manifold. • Locate the manifold in a central position within the zone area. Choosing a central location will save on the amount of pipe and manifold ports to be used. • Make sure that the manifold will be accessible after construction is complete. Manifolds are often under counters and stairs, in utility rooms or in the hot press / airing cupboard. • Manifolds should be positioned 300mm to 450mm above the finished floor surface. They can be mounted on walls or studs. If no wall exists simply mount the manifold on a temporary structure during the construction phase. • The manifold is now in position and ready to be connected to the flow and return from the boiler and the underfloor heating circuits. • A set of self adhesive labels and tags are provided to identify each circuit on the manifold. • The flow meter on each port of the manifold give a clear indication of the flow through each circuit. system components Mixing Valves Thermostatic mixing valves are used if either the temperature or flow rate of the incoming stream frequently changes. This valve reacts to temperature changes of the incoming fluids by opening or closing its inlet ports as necessary to maintain a fixed outlet temperature. Underfloor heating systems require lower temperature water (typically 38ºC - 45ºC). The valve supplied by QPL is either a 22mm or 28mm Heat guard® UFH Blending Valve. Both area high flow thermostatic blending valves for underfloor heating applications. 22mm mixing valve Features and Benefits • • • • • • High flow rates: - 22mm suitable for systems up to 200 sqm. - 28mm suitable for systems up to 300 sqm. Superb temperature control. Quick reaction to supply temperature changes. User adjustable between 30°C and 60°C. Compression type connections for ease of installation. Lockable temperature adjustment mechanism. 28mm mixing valve 35 36 system components Description : Thermostatic blending valve available with 22mm / 28mm compression connections. Suitable for blending the supply and return to achieve a stable system temperature in underfloor heating systems up to 200 / 300 square meters. The 22mm valve comes factory set at 43ºC so this does not have to be adjusted unless diffuser plates are being used in which case it will have to be reset to approx. 60ºC. The 28mm version is set at 30ºC, so it will need to be adjusted for most UFH systems. returned from the underfloor circuits will flow back into the mixing valve, the remainder of which will flow through the bypass and return to the boiler. The lower section of this unit is divided into two isolated sections; mixed water will be pumped into the flow manifold out of the right section while the return water from the bypass will flow out of the left section back to the boiler, there is an internal divide to the right of where the bypass enters the bottom section. Floor Mixing Unit The Pre-assembled mixing unit (Fig. 1) is mounted on a set of brackets and consists of a mixing valve, drain valve, bypass/bypass valve, air vent, and temperature gauge. It is designed to fit directly on to any existing underfloor manifold and allows a standard 6 meter head pump to be fitted (Fig. 2). The unit saves roughly two hours labour during the plumbing of the manifold due to only a flow and return pipe work been required (no complicated elbows). Fig. 1 Operation: Hot water from the boiler enters the unit from the top left and is drawn through the mixing valve by the pump. The mixed water (both boiler and return water) is then pumped through the flow manifold (bottom right). The majority of the water Fig. 2 Circulating pump There must always be a circulating pump installed between the mixing valve and the flow manifold. This pump ensures fast delivery of the mixed hot water to the whole floor area when required. Accurate calculation of the pump duty is necessary to ensure a correct water flow though the manifold and pipe circuits. The standard pump is a 6m head pump. typical system layout typical system layout 37 38 system control system control All heating systems must have proper and correct controls to maintain and achieve comfortable living conditions, energy efficient operation and comply with current building regulations. Programmable room thermostats Full digital thermostat with 4 user programmes and 9 fixed programmes, powered by 3 batteries (supplied), high accuracy, easy to install and programme. They require a 2 core electrical cable for supply. To get the best results from your underfloor heating system QPL recommends individual room control. A room thermostat controls the actuator heads that open or close the pipe circuits specific to that area. The room thermostat system also takes into account all other heat sources including sunshine, body temperature and ancillary heat sources (cooker, stove). There are various types of controls available from boiler controls to air temperature controls to wireless control. Some controls offer various additions such as night setback facility, separate time and temperature controlled thermostats (i.e. programmable), wet area thermostats. Centralised wiring centre units are also included to provide complete system control to include boilers, radiators and domestic water. Wet area probe and sensor box The sensor is supplied with 3m of cable and allows the room thermostat to be installed outside the wet area. Removal of the cover allows the sensor to be used as a floor temperature sensor if preferred. Quality Plastics provides a comprehensive product range of these types of controls. Standard Components Room / Air Temperature Control. Electronic room thermostat with night reduction mode. Can be used to regulate either the floor (with the addition of a sensor) or room temperature or combined. Room thermostats require a 4 core electrical cable for supply. Hard wired Master modular 4 zone wiring centre The master 4-zone wiring centre is a connecting box with all the main connections for an underfloor heating system. This is Din rail or wall mounted close to the manifold and connects room thermostats to their corresponding actuators. Actuator states (open/closed) are indicated by green LED’s; boiler and pump states (on/off) by red LED’s. Includes a volt free contact to connect to an external power supply. It is possible to add more zones by plugging in Slave connecting boxes. system control 4/6 Zone Slave Wiring Centre This 4 or 6 zone slave unit is an additional connecting box which needs to be connected to a master 230 V wiring centre to add more zones in order to connect more thermostats and more actuators. Actuators The electrothermic actuators are used for ON/OFF control of the opening and closing of a particular underfloor heating circuit on the manifold, (through a switch live by a room thermostat.) When the blue indicator is visible, the actuator is fully open. Allow approx 2.5-3 minutes to energise from the fully closed position to the fully open position. 4 channel time clock Four switches operated by a clock to control 4 separate heating systems independently. The user can choose one or more on or off cycles, daily and even weekly cycles depending on user preference. Heating Control Panel This multi-functional panel with L.E.D. light indicators can incorporate the underfloor heating system for both ground and first floor (if required), domestic hot water and a radiator system. It is extremely versatile due to the fact that it has a 3 or 4 zone capability, priority to hot water, connection for boiler and primary pump, boiler interlock provision, motorized valve control, connection for time clock and individual zone control provision. It is suitable for pumped zone systems and has provisions for room thermostats, thermoelectric actuators and external wiring centre units. Quite simply, all the heating system control electrical connections are in one box. 39 40 system control Wireless / Radio Frequency (RF) Control System The advantage of using an RF controlled system is that there is no need for any cables to be installed to accommodate any individual room thermostat. It is ideal for retro-fitting in a building or simply for the speedy installation of an underfloor heating control system. Every radio frequency controlled room requires its own individual RF thermostat. Each RF thermostat is then allocated an individual frequency to communicate back to the RF master wiring centre. This unit has a distribution range of approx 50m and the signal is received through an attached antenna. This antenna receives the signal from the RF room thermostat and opens or closes the thermoelectric actuators accordingly. This whole unit can be placed near the manifold and the only hard wired connections to it are the actuators and power supply. RF Master modular 4 zone Wiring Centre The master 4 zone is a connecting box with all the main connections for an underfloor heating system. Similar in function to the standard hard wired unit. RF Slave 4/6 Zone Wiring Centre This 4 or 6 zone slave unit is an additional connecting box which needs to be connected to the master 230 V wiring centre to add more zones and to connect more thermostats and actuators. RF digital thermostats These stats can be used specifically with the radio frequency receiver. Digital display indicates all temperature and different modes. Controls to receiver by radio transmission. RF Single Zone Receiver There is also the option of a single zone receiver, which is designed for use with one RF thermostat only. Ideal for a single zone application. RF programmable room thermostats These stats can be used specifically with the radio frequency receiver to provide separate time and temperature control for a particular zone. Digital display indicates all temperature and different modes. Controls to receiver by radio transmission. Also the added benefit of having a time control similar to the time clock : Weekly, daily, hourly. system control System Operation and Guidelines : Once installation is complete, set the thermostat to the desired room temperature and / or setback mode. The thermostat in any particular room / zone must then be connected (using cables or RF signals) to every pipe circuit in that room / zone, through thermoelectric actuators sited on the return side of the underfloor heating manifold. Some guidelines to the positioning of room thermostats : • Room thermostats be installed at a height of 1.5m in occupied spaces and at least 50cm away from any adjacent walls. The heating control panel may also be used as the overall controller and this unit contains all the necessary relays to energise the pumps and boiler as well as control for the underfloor heating and if desired, radiator and domestic hot water circuits. Suggested cable sizes to be used : • Main UFH system pump : 3 core cable – 1.5mm / 5 amp • Digital room thermostat : 4 core cable – 1.5mm / 5 amp • Programmable room thermostat : 2 core – 1.5mm / 5 amp • The stat should be located in the area it controls • 4 channel time clock / programmer : 3 core – 1.5mm / 5 amp • The stats must not be exposed to direct solar radiator • Fused spur to control : 4 core – 1.5mm / 5 amp • Avoid external walls • • Avoid recesses and alcoves Heating control Panel : 4 core – 1.5mm / 5 amp • Do not install near lamps or above radiators • Avoid chimney walls • Do not install directly adjacent to doors • Do not install behind curtains • Do not fit to walls concealing hot water pipes Both room thermostats and actuators can be wired directly into the master (or slave) wiring centre. The underfloor heating pump can also be controlled by the wiring center. If any one thermostat calls for heat, it powers the secondary underfloor heating pump as well as the boiler and primary pump (via the relay – not supplied). Once all the thermostats are satisfied the secondary underfloor heating pump shuts down, hence shutting down the boiler and primary pump. Time control and temperature setback For mixed heating systems it is advisable to use an independent time switching service for different emitter circuits e.g. radiators and underfloor heating. An underfloor heating system will respond relatively slowly when compared to the traditional radiator heating system, and will therefore benefit from an offset in timing. The response of the under floor heating system is dependant on the amount of heat energy stored in the floor. To improve response times it is advisable to setback the room temperatures by approx 3ºC during periods where rooms are unoccupied. This can be achieved by using the set back facility on the room thermostat, with an additional wire required for this time switch connection. This method of control usually has the additional benefit of improving the energy efficiency of the heating system. 41 42 system commissioning and setup system commissioning and setup Pre-liminary check • • • • • Floors should be dry before beginning commissioning. The building work should be complete with all external doors and windows closed. If doors and windows are open or solar gain is affecting some rooms, the commissioning will not be accurate. All safety checks relating to boiler operation, system controls, wiring and water connections should have been performed before hand. A routine check on all aspects of the system should be carried out, even though some items may have been installed by others. It is important to know that the boiler is operating, water is flowing towards the system and that electricity is connected. Flow Meters Flow regulation and interception device with set calibration memory and regulated flow display system. Simple, direct calibration by means of an indicator which displays the circuit flow. The special design also makes it possible to clean the window or replace the entire measurement component without draining the system. To adjust the flow meter to achieve correct flow in each circuit : • Adjust the flow meters as described to balance the system. Filling • • • • • • • • • All other heating zones (radiators / primary hot water) should be turned off and isolated. The isolating valves fitted on the underfloor heating zone should be turned off. Connect a temporary mains water supply to the supply manifold and an open hose to drain on the return manifold header. Ensure that all built-in valves are turned off. Turn on the water supply and open the built in valves to the first circuit. Allow water to flow through the circuit and out to drain. When you are satisfied that all the air has been purged from the circuit (the water is flowing full bore), close off the built-in valves to that circuit. Repeat this operation for each circuit. Disconnect the temporary water supply and drain hose, open the isolating valves and allow the manifold headers to fill. Finally open all the supply manifold valves. Check all joints for leaks. The adjustment operation is carried out in the following way. 1. Turn the ring nut, A, anti-clockwise, until the lock shield is completely open. 2. Lower the ring nut, A, and calibrate using the adjuster, B, until the correct flow is reached (directly indicated by the loading capacity measure) 3. Raise the ring nut, A, until it clicks, indicating that it is in the correct (locked) position. It is also possible to seal the ring nut into this position using a lead seal and the holes in the vanes (C) to fasten it: • • directly to the manifold, preventing any tampering. to the flow meter, making it possible to intercept the flow without changing the set calibration for maximum opening. system commissioning and setup Cleaning the window • The system is allowed to operate for a period in excess of 36 hours, to ensure proper circulation to all circuits. • Check the required surface temperature is achieved in each zone. If the temperature is too low, increase the flow rate. If the temperature is too high, reduce the flow rate. Note : Remember that heat changes slowly in underfloor heating systems and it will take some hours before the result of any adjustments will be noticed. Therefore, take note of each adjustment and the effect on the system for future reference. When the final floor coverings are laid, the system flow rates may need to be re-adjusted. System Start up • • • • • • Turn the ring nut, A, clockwise, until the lock shield is completely closed Remove the window by unscrewing the adjuster, B Clean the window and screw it back on with the adjuster, B Turn the ring nut, A, anti –clockwise, until the lock shield is completely open System setup • • • • • • • • The supply water temperature is correctly set on the mixing valve for the maximum required temperature. • The system is proportionally balanced. • Each circuit is balanced to give the design flow rate. • Ensure the boiler and boiler pipe work is filled; check for and repair any leaks. Ensure the distribution system (underfloor loops) are correctly filled and purged of air. This is usually done one manifold at a time. It is recommended that circuits are filled and purged individually. System should be cleaned and flushed. Flow meters are set as specified, settings checked. Set the desired supply water temperature on the mixing valve to achieve the design supply water temperature for each zone. Set pressure differential bypass valve if used. Start and operate the boiler or heat source. Proper and safe operation of boiler verified, (refer to the boiler manual) venting system, controls and safety devices. After running the system for 24 hours verify that there is a normal temperature difference between the system supply and return. Typical 5°C-10°C. With zones running under load, the boiler should cycle. If not: re-purge, check circulator operation, check control valves, and check boiler operating temperature. 43 44 guideline for homeowners System Water Treatment Although Qual-PEX barrier pipe virtually eliminates the permeation of oxygen through the pipe wall, there are other points in the system which can potentially allow oxygen into the system, e.g. shut-off valves, vents etc and this can have a detrimental effect on ferrous parts in the system. For this reason a corrosive inhibitor should be used and QPL recommends the following : • A silicate based corrosion inhibitor in concentration of 0.95 liter per 190 liters of water. • A borate – nitrate corrosion inhibitor in concentration of 1400 ppm / 0.95 liter treatment per 95 liters of water. Maintenance As with all types of heating systems, the moving parts associated with UFH may need maintenance from time to time. • The boiler should be serviced annually by an approved technician. The manifold should be checked to ensure that there are no leaks on unions or valves. • All mixing valves, pumps (both primary and secondary), room thermostats, thermoelectric actuators etc should be inspected visually at least once a year. guidelines for homeowners 1. Turn the system on at the start of the heating season and allow it to operate continuously throughout. 2. On / off time switching of the system is a false economy and will lead to poor control and reduced fuel efficiency. 3. Where the controls are suitable the system may be switched to setback conditions if and when desired. 4. Room thermostats should be set to maintain the required room temperature and not used as manual switches. With underfloor heating systems it is usual to feel quite comfortable at lower room air temperatures (18oC) than normally required with radiators (21oC). 5. Underfloor heating systems have a high thermal mass and therefore will respond slowly to a call for heat after a period of inactivity. design considerations design considerations • When installing any under floor heating Boiler size: system, there are a number of factors • which affect its efficiency. The commissioning sheet contained within this specification details the boiler size required for the underfloor heating only. • In cases where the design specification is not strictly adhered to, high fuel bills may • • The load for any additional radiators and result leading to call-backs to a particular domestic hot water will need to be added to job and changes to the system. this, to give the final boiler size required. This has also in the past lead to false • It is vital that this boiler size is strictly speculation that under floor heating adhered to, as over sizing will lead to systems are troublesome and inefficient. wasted energy and hence increased fuel bills. • When installed correctly, a Qual-PEX ‘Cosy Home’ under floor heating system will work Running times: out more efficient in terms of running cost • Under floor heating systems operate more and will be of superior comfort over efficiently on the basis of continuous conventional heating systems. operation. Ultimately this benefits everybody. It is vital that • On/Off time switching of the system will result in fluctuating floor temperatures and the following points are strictly adhered to: hence an additional load on the boiler. Primary Loop: • The boiler schematic contained within this specification shows the recommended method of installing distribution pipe work between the boiler and manifold. • This method of installation will prevent low temperature water being circulated through the boiler which will significantly reduce the efficiency of the boiler by requiring it to be on for long periods of time to heat the return water back up to the supply water temperature. • The setback facility of the controls supplied should be utilised. 45 46 trouble shooting guide trouble shooting guide All rooms are cold : If running costs are high • Check time clock Check : • Check thermostat setting • • Check boiler operation correctly electrically connected to the boiler • Check the supply water temperature is to prevent short cycling and to ensure that correct the boiler is not running when it is not • Check all valves are open required. • Check pump operation • That the underfloor heating system is That the temperature in the rooms and the thermostat settings are as specified. Individual rooms are cold • For any open windows. It is not unknown • Check thermostat setting and location for windows to be opened in cold weather • Check thermostat is operating the relevant as the internal comfort remains constant actuator head with thermostatic controls. • Check actuator is operating properly. The • That the boiler is operating correctly. actuator opens when energized. • That the floor has been properly insulated • Check system is correctly balanced • Check circuit valves are open • Purge air from circuit • Check circuits are not cross connected at the construction stage. Flow rates: • The attached commissioning sheet (in the design specification brief) details All rooms are hot the calculated flow rates for each individual • Check thermostat setting circuit. These circuits can be balanced by • Check position of indictor of mixing valve setting the flow meters on the supply mani • Check pump speed. Too high or low? fold to correspond to these flow rates. • Check the supply water temperature is correct • Greater flow rates than those required will lead to an additional load on the boiler, resulting in it being on for longer periods of time, thereby reducing efficiency. If the system is noisy Check : • That there is no air in the system • That all pipes are firmly clipped in place and the manifold brackets are tight • That excessive pressure from another pump in the system is not interfering with the underfloor system. frequently asked questions frequently asked questions Why would I put underfloor heating in my house? Can the underfloor heating system be run from my existing radiator system ? • • NO. The underfloor heating is designed as a separate heating system and is best left as an independent system run directly for the boiler. The only exception to this is when a conservatory / extension UFH kit is used which allows a single room to be underfloor heated off the main radiator circuit. • • • • • • • Comfortable even temperature throughout Efficient on fuel due to lower operating temperatures Healthier environment with less dust being circulated Safer—no hot panels or dangerous hard edges No restrictions on interior design layout Low maintenance Maximum usable floor spaces Excellent value for money Independent temperature control for all rooms. What is the maximum area that can be covered? The is no maximum area that can be covered. The possibilities are endless. What comes in a standard underfloor kit? The Qual-Pex Cosy Home kit comprises : • A number of coils of 15mm Qual-PEX pipe • Manifold(s) as required • Zone circulating pump(s) Mixing valve with temperature setting • • Room thermostat (s) Thermo-electric Actuators (to control each • circuit) • A wiring centre for ease of electrical connection • Heating control panel (overall system control) • Options on various fixing systems and insulation. What is not included in the underfloor heating kit? Insulation, concrete screed, supply and return pipe to connect to boiler and / or existing heating system and boiler are not included. Can the underfloor heating be run from my boiler as a separate system ? YES. This is the best method for running the underfloor system as it will operate as a separate zone system with direct boiler control. It can then be controlled separately from the rest of the heating systems in the house. What type of boiler can I use in conjunction with the under floor heating system? This type of heating system may be used in conjunction with any oil or gas fired boiler or even a geo-thermal heat pump system. It is not recommended however to run the system from a solid fuel heat source. When should I install the underfloor system? The underfloor heating can be installed during the build process of the dwelling on top of the sub floor and a layer of insulation. What type of insulation is to be used ? The insulation may be either 60mm Foil-Backed Polyurethane or 100mm High Density Polystyrene. Where do you install Edge insulation ? 25mm edge insulation should be installed around all the perimeters of each room. This is often installed by the builder. How do I fix the underfloor pipework down ? Rapid rail and clips are used to hold the pipe in place before the screed is poured. Alternatively, wire mesh and cable ties may be used to secure the pipe. What pipe size shall I use ? 15 mm Qual-PEX Barrier pipe is used for the underfloor heating circuits. This pipe is supplied as part of the kit from QPL. What is the guarantee on the pipe ? The pipe is guaranteed for 25 years and has a life expectancy of over 50 years. Is the pipe approved ? Qual-PEX 15mm Barrier Pipe is BSI Kitemark approved for use under the service conditions listed in BS 7291 : Part 1 : 1990 Class S : 12 bar at 20ºC - 4 bar at 82ºC - 3 bar at 92ºC with a short term overload temperature of 114ºC. 47 48 frequently asked questions What is the maximum loop length ? What is the water flow temperature ? The maximum loop length for 15mm Qual-PEX is 100m. It is not advisable to make the loops longer than 100m because the pump used is only capable of pressurising water through 100m of pipe. The mixing valve has a temperature setting range of between 30ºC and 60ºC and should be set to ensure that the floor surface temperature should never exceed 29ºC. What are the lengths of the pipe loop ? What is the maximum temperature difference ? The length of the circuit depends on the area covered, and is detailed in the design specification. The pipe is marked every meter making it easy to cut to length. The system is designed to work with a temperature difference between the flow and the return of 7ºC 10ºC. How do you lay the pipe ? Always lay the pipe in order of heat output importance, for example; What are the best types of floor finishes to suit underfloor heating ? • 1. Cold spots first. (External walls). 2. Inner walls (Internal wall). • 3. Follow the standard diagram provided in the instructions • • What is the distance between pipe and perimeter walls ? The pipe distance from walls should be 100 mm. What is the minimum and maximum depth of screed to cover the pipe work ? The minimum depth of screed above the insulation is 65mm and the maximum is 100mm What is the drying out time for the concrete screed ? The screed drying time can be 4 to 6 weeks before the underfloor heating system is operated. A good rule of thumb is 1 week per 1” / 25mm of screed. The mixing valve needs to be set at minimum temperature when commissioning the system. Increase the temperature by 2 to 3 degrees everyday. This will avoid the screed cracking.The screed must be allowed to dry out fully before the system is commissioned What is the heat up time of the underfloor slab? The heat up time will take several hours from initial start up of the system to achieve satisfactory floor surface temperatures of approx 25ºC to 29ºC. What is the cool down time of the underfloor slab ? The slab will take several hours to cool down once the system is fully switched off. This time may differ depending on the screed depth and the duration of the system running • Tile, carpet and timber are all suitable floor coverings. There are a few design considerations to be adhered to : Tile : Use special adhesive suitable for undefloor heating Timber : Use timber that has been kiln dried to approx 8%. Carpet : Always use a good quality thin carpet and a good quality underlay. Always consult your flooring provider before you lay a finished floor on top. They will provide you with the best advice on choosing a floor covering most suitable for underfloor heating Is it More Expensive Than Radiators to Install? The initial investment is higher than a radiator system but the end result is lower running costs, a better form of comfort and a hidden heating system Is it a complicated system to install? All QPL underfloor heating systems are relatively easy to install. Simply follow our AutoCAD design drawing for the pipe patterns and loop lengths. A full design specification goes out with each project detailing zone layouts, commissioning details, system setup and operation and of course all mechanical and electrical diagrams and data sheets. Are we confined to just underfloor heating? Not at all. You can incorporate underfloor heating with a radiator system and domestic hot water can also be accommodated from the primary circuit. This allows you to have individual control over the three systems. Will I have control over each zone? Yes. Individual room thermostats are supplied for each room or zone allowing you to have a completely independent zone-by-zone system. notes 49 50 notes QPL Ireland Pipelife UK Depot P.O. Box 29 • White’s Cross • Cork • Ireland Tel: +353-21-488 4700 •Fax: +353-21-488 4706 Email: [email protected] Web: www.qpl.ie 13 Saxon Way East • Oakley Hay Industrial Estate • Corby • Northants • NN18 9EY. Tel: 0845 2419 490 • Fax: 0845 2419 491 Email: [email protected] • Web: www.pipelife.co.uk