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Service Bulletin Booklet For Compact model water heaters GWH 260 PN, GWH 425 PN, GWH 425 HN GWH 1000 P, GWH 1600 P, GWH 1600 H CT-02 page 1 of 1 rev 10/06 THERMOCOUPLE AND PILOT TEST MODELS: 1000P, 1600P, 260PN, 425PN WARNIN G ARNING LP & N G ARE EXTREMEL NG EXTREMELY FLAMMABLE Y FL AMMABLE SO UTIONS WHEN PRECAUTIONS TAKE EXTRA PRECA PERF ORMIN G ANY W ORK T O THE HEA TER PERFORMIN WORK TO HEATER Before replacing the thermocouple, please test the thermocouple safety circuit and the pilot as follows. A. Pilot does not stay lit when the button is released. 1. When lighting pilot, ensure the gas valve button is fully depressed and held down for at least 15 seconds after pilot is lit. 2. Pilot flame should be a shar p blue flame that fully engulfs the thermocouple tip. If pilot doe s not look this way, please see bulle tin ‘CT-22 Cleaning pilot assembly’ for instr uctions on how to clean pilot a ssembly and or ifice. 3. If heater is equipped with an AQ4 power vent kit (models 1600P and 425PN only), press reset but ton on power vent spill switch to c heck if it is tripped. NOTE: r unning the heater without electrical power to po wer vent fan will trip the spill switch. Also check the AQ4 safety circuit connections for corrosion or loose connections. Consult AQ4 manual for par t locations. 4. Check the electromagne t connections. The electromagnet is located on the back side of the gas valve. The electromagnet connection from the thermocouple is a 5 mm brass nut tha t screws into a 17 mm aluminum nut. Tighten both nuts snugly but do not over tighten. 5. Check if connections at both temperature limiters (ECO) are loose or corroded. Cle an any corrosion with very fine sand paper or an eraser and reconnect leads. 6. If cleaning the terminals attac hed to the ECO’s does no t fix the problem, choose one EC O and remove tw o wires attached. Connect a jumper wire between the two wires removed from the ECO. Try to relight the pilot. If the pilot flame now remains on, the ECO may be defective. If the pilot still goes out, remove jumper, r econnect wires leads and perfor m the same step wit h the other ECO. Note: Never attempt to operate heater for normal use with jumper wire connected! 7. Replace ECO. 8. Have a licensed gas technician verify the proper operation of the thermocouple. To test the thermocouple, disconnect wire from the thermocouple where it connects to the upper ECO (located top right side of the heat exchanger). Insert a multimeter probe into the ther mocouple lead and attach or hold the other probe to the metal chassis of the heater (DC common). Light the pilot flame and hold button while obser ving the me ter reading. If the reading is 24mVDC or more the thermocouple is good. ©BBT NORTH AMERICA CORPORATION Bosch Group B. Pilot goes out during use 1. Light the pilot and allow it to warm the ther mocouple tip for 2 minutes. 2. Perform dr op test by blowing out the pilot flame and listen for the electromagnet to close. This closure will make a distinct clunk noise as it shuts. The time between blowing out the flame and the electromagnet closing should be between 20 and 30 seconds. Units equipped with an AQ4 power vent kit have drop times between 10 and 15 seconds. 3. Repeat drop test several times to confirm it is consistent 4. If drop times are not within specifica tions, then follow steps 2-7 in section A . After each step, repeat drop test. Proceed to the next step until drop test is within specifications. C. Pilot goes out during use and drop test is within specifications. 1. Check the vent size and length. Vent should be 5 inches in diame ter for the 1600P and 425PN and 4 inches in diameter for the 1000P and 260PN. The heater mus t have a rise of 1foot before any elbo ws in the vent system, at least 6 feet vertical in length and terminate through the r oof. Any reduction in vent size or the presence of an elbow directly on the top of the unit may cause the flue gas sensor to trip the pilot safety circuit. Please see t he venting section in the manual for more de tailed information regarding the required venting for this heater. 2. Inspect the draft hood and heat exchanger fins for signs of soot build-up or any other foreign material such as spider webs. Clean out an y debris found in the vent hood. Signs of soot indica te insuf ficient combustion air or exhaust draft. Check for vent assembly bloc kage or combus tion air blockage on the underside of the unit. Ensure combustion air requirements are being met as specif ied in the installation manual. 3. Measure the outgoing temperature of the hot water exiting the unit. Temperature in excess of 160F may trip the pilot safety circuit. The heater must not be supplied with w ater in excess of 90F. Preheated water may cause the heater t o overheat t he outlet water and shut down as a safety precaution. Bosch Water Heating 340 Mad River Park, Waitsfield, VT 05673 CT-03 page 1 of 1 rev 09/06 CHECKING THE DRAFT MODELS: 1000P, 1600P, 1600H 260PN, 425PN, 425HN 1. Close all doors and window in the building. 2. Operate all fuel burning appliances and exhaust systems in the building with the exception of the tankless water heater. Allow time for these items to utilize the air in the structure. Up to one hour ma y be necessary. 3. Remove the cover from the tankless unit and hold a recently extinguished match, candle, or any other visible smoke source in front of the triangular opening on the dr aft diverter. 4. The smoke should be sucked quickl y into the opening and up the exhaust vent. If the smoke is blown back, a negative air situation exists and must be corrected. See the combustion air section in the manual or bulletin CT-05 Negative air and freeze prevention. 5. Now run the heater for 10 minutes, then hold a smoke source at the top right side of the draft diverter. The smoke should be drawn in the louvers on the side. If this is not the case, the unit is not drafting properly and flue gases are being exhaus ted into the space in which the heater is installed. This is not safe and must be corrected. Reference the venting section in the manual to ensure venting is in accordance with the manufacturer’s specifications. WARNIN G ARNING LP & N G ARE EXTREMEL Y FL AMMABLE SO NG EXTREMELY FLAMMABLE UTIONS WHEN PRECAUTIONS TAKE EXTRA PRECA PERF ORMIN G ANY W ORK T O THE HEA TER PERFORMIN WORK TO HEATER Step 3: Hold extiguished match here Step 5: Hold extiguished match here 1000P. 1600P, 1600H, 260PN, 425PN, 425HN Note: Poor venting can result in excessive sooting around the water heater, overheating, and release dangerous carbon monoxide into the living space causing serious injury and/or death. Note: Damage to the heater as a result of improper venting will not be covered under warranty. ©BBT NORTH AMERICA CORPORATION Bosch Group Bosch Water Heating 340 Mad River Park, Waitsfield, VT 05673 CT-04 page 1 of 1 rev 10/06 CHECKING GAS PRESSURE MODELS: 1000P, 1600P, 1600H 260PN, 425PN, 425HN A. Connecting manometer: WARNIN G ARNING LP & N G ARE EXTREMEL NG EXTREMELY FLAMMABLE Y FL AMMABLE SO UTIONS WHEN PRECAUTIONS TAKE EXTRA PRECA PERF ORMIN G ANY W ORK T O THE HEA TER PERFORMIN WORK TO HEATER FIGURE 1 1. Tur n off gas using installer supplied manual shutoff. 2. Remove front cover (see manual for instructions) and locate inlet gas pressure tap above the regula tor on the gas inlet pipe and the manifold gas pressure tap on the right side directly belo w the burner (F ig. 1). 3. Select appropriate pressure tap per specific pressure test (see steps B and C). Loosen the screw fr om test point fitting (do not remove) and connect manometer tube on test point. B. Static pressure test (Inlet pressure tap only) 1. 2. 3. 4. Tur n gas supply back on. Operate all other gas appliances at maximum output. Record static pressure reading in Table 1. Leave manometer connected to inlet tap for oper ating pressure t est. Mainfold tap Inlet tap C. Operating pressure test 1. Light pilot if neccessary (1000P, 1600P, 260PN and 425PN models). 2. All other gas appliances should still be running at full capacity. 3. Set heater to maximum output: 1000P, 1600P, 260PN, 425PN: Set gas slide control to the right. Turn temperature adjustment knob full clockwise. 1600H, 425HN: Turn power adjustment knob full clockwise. Tur n temperature adjus tment knob full clockwise. 4. Open all hot water taps supplied by this unit. 5. Record inlet tap oper ating pressure reading in Table 1. 6. Tur n off gas supply as well as all hot water taps. Disconnect manometer from the inle t tap. Tighten screw in tap fitting or gas leak may occur. 7. Reconnect manometer to the manifold gas pressure tap. 8. Tur n gas supply back on and follow steps 1 through 4. 9. Record manifold tap oper ating pressure reading in Table 1. 10. Tur n off gas supply as well as all hot water taps. Disconnect manometer from the manif old tap. Tighten screw in tap fitting or gas leak may occur. 11. Put cover back on water heater, open gas supply and return heater to service. ©BBT NORTH AMERICA CORPORATION Bosch Group GAS PRESSURE TEST POINTS TABLE 1 Static gas pressure: “ W.C. Required static gas pressure (all models: NG 7” - 14” W.C. LPG 11” - 14” W.C. Operating gas pressure: Inlet Tap “ W.C. Manifold tap “ W.C. Minimum require operating gas pressure: Bosch Water Heating 340 Mad River Park, Waitsfield, VT 05673 CT-05 page 1 of 1 rev 10/06 NEGATIVE AIR & FREEZE PREVENTION MODELS: 1000P, 1600P, 1600H, 260PN, 425PN, 425HN WARNIN G ARNING LP & N G ARE EXTREMEL NG EXTREMELY FLAMMABLE Y FL AMMABLE SO UTIONS WHEN PRECAUTIONS TAKE EXTRA PRECA PERF ORMIN G ANY W ORK T O THE HEA TER PERFORMIN WORK TO HEATER Negative Air Checking for Negative Air • Negative air pressure in a str ucture occurs when air consumed by fuel burning appliances or exhaus t systems in that structure exceeds the amount of air available. • Here is a list of items tha t consume air within a typical household: • Stove exhaust fans • Furnaces • Water heaters • Fireplaces/ Woodstoves • Bath fans • Dryers • All of these items must be taken into account when making provisions for a proper amount of fresh air from the outside. • If the building is new cons truction, air infiltration from the outside will be limited and provisions for extra air supply should be made. If the building is older construction, air may infiltr ate into the house through unplanned sources such as window fr ames, door jams, sill plates or idle chimney flues. These sour ces still may not be providing the adequate amount of air and additional sources of fresh air should be considered. 1. Close all doors and windows in the building. 2. Operate all fuel bur ning appliances and exhaus t systems in the building at full capacity with the exception of the tankless water heater. Allow time for t hese items to utilize the air in the str ucture. Up to one hour may be necessary. 3. Remove the cover from the tankless unit and hold a r ecently extinguished ma tch, candle, or any other visible smoke source in front of the triangular opening on the draft diverter. 4. The smoke should be sucked quickly into the opening and up the exhaust vent. If the smok e is blown back, a negative air situation exists and must be corrected. See the combustion air section in the manual for specifications. 5. Now run the he ater for 10 minutes, then hold a smoke source at the top right side of the draf t diverter. The smoke should be drawn in the louvers on the side. If this is not the ca se, the unit is not drafting properly and flue gases are being exhausted into the space in which the heater is ins talled. This is not safe and must be corrected. Reference the venting section in the manual to ensure venting is in accordance with the manufacturer’s specif ications. Why Negative Air is Bad Cold air from the outside is dr awn through the water heater’s flue pipe because other fuel burning appliances or exhaust systems in the str ucture require more air than the dwelling can supply. When the required amount of air for the fuel burning appliances or exhaust systems in t he structure is not being supplied to them, they find the flue pipe on the water heater an acceptable means of supplying themselves. Thus, freezing cold air is pulled down the water he ater’s flue, drawn o ver t he copper heat exchanger, potentially freezing it and the water valve below. Because, when idle, the water heater holds only cold w ater, fr eezing can happen quickly possibly causing leaks or r uptures in the heat exchanger and/ or the water valve. The water he ater does not pull air through its flue pipe – if you w ere to remove the heater, the air would continue to come down your f lue pipe. You must ha ve the air balanced in the s tructure to correct this pr oblem. Consultation with a heating, ventilating and air conditioning (HVAC) specialist is recommended. Note: Poor venting can result in excessive sooting around the water heater, overheating, and release dangerous carbon monoxide into the living space causing serious injury and/or death. Note: Damage to the heater as a result of improper venting will not be covered under warranty. ©BBT NORTH AMERICA CORPORATION Bosch Group S tep 3: Hold extiguished matc h here S tep 5: Hold extiguished matc h here DRAFT DIVERTER FOR: 1000P, 1600P, 1600H, 260PN, 425PN, 425HN Bosch Water Heating 340 Mad River Park, Waitsfield, VT 05673 CT-06 page 1 of 1 rev 10/06 OVERCOMING FLUCTUATING TEMPERATURES MODELS: WARNIN G ARNING LP & N G ARE EXTREMEL NG EXTREMELY FLAMMABLE Y FL AMMABLE SO UTIONS WHEN PRECAUTIONS TAKE EXTRA PRECA PERF ORMIN G ANY W ORK T O THE HEA TER PERFORMIN WORK TO HEATER 1000P, 1600P, 1600H 260PN, 425PN, 425HN Introduction Lower temperature Temperature fluctuations from hot to cold during use is typically caused by a back pr essure on the water flowing t hrough the tankle ss water heater. This decreases the flow rate through the tankless water heater belo w the required activation flow rate and shuts the heater down. Follow these instructions step by step to overcome this phenomenon. The tem perature can be lowered by moving gas slide control to the left. On models 1600H and 425HN, turn power adjustment knob clockwise. See bulletin CT-07 Lowering temperatures for alternative methods of lowering output temperature. Clean faucet aerators and shower heads 1. 2. 3. 4. 5. Check for restrictions in outlets, which would limit hot water demand and may assist in de activation scenario. For sinks, remove faucet aerator on end of sink. Flush and cle an screen and reinstall. For showers, remove sho werhead and f lush. If plugge d wit h mineral deposit s, cle an accor ding t o manufacturer’s suggestions or replace. (Note: if showerhead is wand style/hand held, corrugated tube connecting to head may be too restr ictive. Enlarging tube or using a normal showerhead may be the solution.) Clean Inlet filter screen Inlet filter screen is located in bottom of the water valve near the cold w ater connection side (right) at t he rear of the unit. Please see bulletin CT-12 Cleaning inlet f ilter for more detailed instr uctions. Check for plumbing crossover Confirm activation rate of the heater Turn flow control knob on the front of heater fully clockwise. Fully open one hot water tap. Return to heater and shut cold water supply valve. Slowly open cold water supply v alve until the burners ignite. Return to hot water tap and measure f low rate by timing how long takes to fill a quart container. A fill time of 30 seconds indicates a proper activation rate of 0.5 gallons per minute (GPM)*. See Table 1 for other flow r ate conversions. 6. Repeat steps 4 and 5 a few times to check the accuracy of test. * A fill time less than 30 seconds indicates an activation rate above the required 0.5GPM and a pos sible problem within the heater’s water valve. Periodic maintenance is required on this water valve. Visit our w ebsite for par ts and ser vice bulle tins for t his procedure. GPM Qu ar t Jar Gallo n Ju g .50 30 1 20 .75 20 80 1.00 15 60 1.25 12 48 1.50 10 40 (in Secon ds) (in Seco nds) A plumbing crossover can be caused by a failed car tridge at a single lever fauce t, incorrect plumbing or a faulty mixing valve in the piping. The crossover will cr eate a back pressure on the water heater and prevent an a dequate flow of w ater through it. Close installer supplied cold water shut off valve to the heater (if none installed, install bef ore proceeding). Open all ho t water taps supplie d by the heater. Wait 5 minutes and check all taps. Water running is a sign of a plumbing cross-over. Consult a local plumber or service person for help in correcting a plumbing crossover. 1.75 8.5 34 2 .0 0 7.5 30 Confirm water pressure 2 .5 0 6 24 Water pressure should stay above 30psi during operation. If on a well system, we recommend a pressure setting of 40-60psi. 3 .0 0 5 20 3 .5 0 4 .2 5 17 4.00 3.75 15 TABLE 1 ©BBT NORTH AMERICA CORPORATION Bosch Group Bosch Water Heating 340 Mad River Park, Waitsfield, VT 05673 CT-07 page 1 of 1 rev 10/06 LOWERING TEMPERATURE MODELS: WARNIN G ARNING 1000P, 1600P, 1600H 260PN, 425PN, 425HN LP & N G ARE EXTREMEL NG EXTREMELY FLAMMABLE Y FL AMMABLE SO UTIONS WHEN PRECAUTIONS TAKE EXTRA PRECA PERF ORMIN G ANY W ORK T O THE HEA TER PERFORMIN WORK TO HEATER When the temperature adjustment knob on the front of heater is turned all the way clockwise (hotter temps.), the heater requires a 0.6 gallon per minute flow rate to activate. When the temperature adjustment knob is turned all the way counter-clockwise (cooler temps.), the unit will require a 1.1 gallon per minute flow rate to activate. Although common sense tells us to turn this knob counterclockwise to achieve a lower outlet temperature, we recommend that the temperature adjustment knob be kept all the way clockwise, to take advantage of the 0.6 gpm activation point. Please move knob to this setting and follow the steps below for alternative ways of lowering temperature. FIGURE 1 Solution: Increased water flow helps to lower the outle t temperature and ensures that the heater stays activ ated especially when mixing cold water at the outlet. 1. Increase the flow by cleaning the inlet filter screen in the heater. (Fig. 1) Consult bulletin CT-12 Cleaning inlet filter for more detailed instructions on removing the inlet filter. 2. Increase the flow at all outlets. For sinks, remove faucet aerator screen on end of sink. Flush screen with water to clean and r einstall. For showers, r emove showerhead and flush with water. If the he ad is clogged with mineral deposits, clean according to manufacturer’s specifications or replace. Please note, if the showerhead is a hand-held/wand style, these can be extremely r estr ictive. If cleaning or flushing showerheads/aerators fails to produce adequate flow, try upgrading with higher flowing versions. 3. Decrease the gas volume by moving gas slide control (models 260PN, 425PN, 1000P, 1600P) or gas control knob(models 425HN, 1600H) to the small flame position. 4. If temperatures are still too hot, increase water flow by removing the water governor/restrictor. Shut off cold water supply to heater and remove wire clip on volumetric water governor housing from right side of water valve behind water outlet pipe. (F ig. 2) Remove retaining cap with o-ring and spring/cylinder assembly inside. (Fig. 3) Re-install retaining cap with lubricated o-ring and wire clip only. No inner components should be left inside. Operate heater with the flow control turned all the way clockwise. ©BBT NORTH AMERICA CORPORATION Bosch Group Removing Water Filter FIGURE 2 Water governor clip Water Governor Location FIGURE 3 Retaining cap Cylinder Spring Water Governor Location Bosch Water Heating 340 Mad River Park, Waitsfield, VT 05673 CT-08 page 1 of 1 rev 10/06 DESCALING MODELS: 1000P, 1600P, 1600H 260PN, 425PN, 425HN WARNIN G ARNING LP & N G ARE EXTREMEL NG EXTREMELY FLAMMABLE Y FL AMMABLE SO UTIONS WHEN PRECAUTIONS TAKE EXTRA PRECA PERF ORMIN G ANY W ORK T O THE HEA TER PERFORMIN WORK TO HEATER Instructions for removing scale from heat exchanger. 1. Disconnect electrical supply from the water heater. 2. Shut off the water supply to the water heater using (installer supplied) isolation valve. 3. Open hot water taps to drain and r elieve pressure from the plumbing system. 4. Drain water from the unit’s heat exchanger b y disconnecting inlet and outle t water connections. 5. Connect the line (A) from the outlet of the circulating pump (installer supplied) to the inlet water fitting on the water heater. 6. Using another line (B), connect to the water outlet fitting on the water heater. Route the other end of this line into a descaling reservoir. 7. Using a 3r d line (C) from the descaling reservoir, connect to the inlet side of circulating pump. Verify there is a filter on the end of the line in the descaling reser voir. 8. Make sure all connections are “hand tight.” 9. Fill tank with descaling solution so lines inside are submersed. We recommend a straight white vinegar solution. If using a commercial descalant, ref er to manufacturer’s instructions on dilution with water. 11. Operate the circulating pump. 12. Make sure there are no leaks and the solution is flowing from the descaling reser voir through the heat exchanger and returning t o the reservoir. 13. Run solution through the heat exchanger until the solution returning to the descaling reservoir comes out clear. (Changing to a fresh solution may be necessary during this process) 14. Disconnect all lines and drain all solution from heat exchanger. Proper ly discard solution. 15. Position a container below the hot water outlet and reconnect cold water suppl y. Open cold water supply isolation valve and flush heat exchanger with clean water. 16. Shut cold water isolation valve and reconnect hot water supply to the water heater. 17. Reconnect electrical supply to unit, open water isolation val ves, and retur n the unit to service. ©BBT NORTH AMERICA CORPORATION Bosch Group B C PUMP A RESERVOIR Bosch Water Heating 340 Mad River Park, Waitsfield, VT 05673 CT-11 page 1 of 1 rev 10/06 WINTERIZING FOR SEASONAL USE MODELS: 1000P, 1600P, 1600H 260PN, 425PN, 425HN WARNIN G ARNING LP & N G ARE EXTREMEL NG EXTREMELY FLAMMABLE Y FL AMMABLE SO UTIONS WHEN PRECAUTIONS TAKE EXTRA PRECA PERF ORMIN G ANY W ORK T O THE HEA TER PERFORMIN WORK TO HEATER Please note that the instructions in the manual state that the water heater must not be installed in a location where it may be exposed to freezing temperatures. If the heater must be left in a space which is likely to experience freezing temper atures (less then 32º F), all water must be drained from the heater. Damage as a result of improper drainage will not be covered under warranty. Draining the heater 1. Shut off gas to heater. 2. Shut off water supply to the heater using installer supplied cold water isolation valve. If none installed, install before proceeding. 3. Open lowest hot water faucet to drain lines and relieve pressure in heater. 4. Position a bucket below water connections to water heater. 5. Remove the retaining clip (F ig. 1, Num. 1) from the thr eaded bushing. 6. Remove the threaded bushing (Fig. 1, Num. 2) from the water valve. 7. Contents of he ater and water lines will dr ain. 8. Removal of piping between the water valve and heat exchanger may be necessar y to ensure all water has been drained (Fig. 1, Num. 3) On Models 1000P, 1600P, 260PN, 425PN: Remove retaining clips at water val ve and heat exchanger connections. On Models 1600H, 425HN: Remove reatining clips at water val ve and base of hydrogenerator. 9. Remove piping and save f or reinstallation when heater is returned to service. FIGURE 1 Note: If using the AQ4 powervent, all flow switch piping should be disconnected and drained. ©BBT NORTH AMERICA CORPORATION Bosch Group Bosch Water Heating 340 Mad River Park, Waitsfield, VT 05673 CT-12 page 1 of 1 rev 10/06 CLEANING INLET FILTER MODELS: 1000P, 1600P, 1600H, 260PN, 425PN, 425HN Removing water filter WARNIN G ARNING LP & N G ARE EXTREMEL NG EXTREMELY FLAMMABLE Y FL AMMABLE SO UTIONS WHEN PRECAUTIONS TAKE EXTRA PRECA PERF ORMIN G ANY W ORK T O THE HEA TER PERFORMIN WORK TO HEATER FIGURE 1 1. Shut off the installer supplied cold water isolation valve to the heater. If one is not installed, ins tall before proce eding. 2. Open the nearest hot water tap to drain the plumbing lines. 3. Position a bucket under the heater’s water valve assembly to catc h any water that may drain from the heater. 4. Remove the retaining clip located at base of water valve (Fig. 1, Num. 1). 5. Remove the threaded bushing (Fig. 1, Num. 2) to access the cy lindrical filter inside. 6. Remove filter, clean with water and inspect for damage. 7. If the filter is at all damaged, it should be replaced. ©BBT NORTH AMERICA CORPORATION Bosch Group Bosch Water Heating 340 Mad River Park, Waitsfield, VT 05673 CT-13 page 1 of 2 rev 10/06 REMOVING AND CLEANING BURNERS MODELS: 1000P, 1600P, 1600H, 260PN, 425PN, 425HN WARNIN G ARNING LP & N G ARE EXTREMEL NG EXTREMELY FLAMMABLE Y FL AMMABLE SO UTIONS WHEN PRECAUTIONS TAKE EXTRA PRECA PERF ORMIN G ANY W ORK T O THE HEA TER PERFORMIN WORK TO HEATER A. Removing pilot assembly Model 1000P, 1600P, 260PN, 425PN (Fig 1): 1. Shut off ga s and water t o heater, then remove front cover. 2. Remove wire clip holding top of pilot tube into bracket. 3. Move lower end of pilot tube to left to release from black clip on gas valve. Be sure to catch air screen attached to base of pilot tube. 4. Pull upwards on upper end of pilot tube to release from bracket. 5. Remove black clip from bracket to release spark electrode. 6. Gently press down on top of thermocouple to release it from bracket. FIGURE 1 FIGURE 2 Pilot shield Pilot bracket screws Burners Pilot air screen Pilot air screen Burner set screws 1600H, 425HN pilot assembly FIGURE 3 Pilot wire clip Pilot tube Burners Thermocouple lead Pilot air screen 1000P, 1600P, 260PN, 425PN pilot assembly Model 1600H, 425HN (Fig. 2): 1. Shut off ga s and water t o heater, then remove front cover. 2. Remove both pilot bracket screws and pilot shield from front of burners. 3. Remove pilot assembly from burner br acket. Be sure to catch air screen secured to base of pilot assembly. Burner bracket location (425PN model shown) FIGURE 4 B. Removing burners 1. Remove 2 burner set screws on the right side of the gas valve. (Fig. 2) 2. Remove four screws from both right and left burner brackets and set aside. (Fig. 3) 3. Push entire burner assembly up to seperate from the gas valve. 4. Tilt right side of burners up and slide them out at an angle to the left. (Fig. 3) ©BBT NORTH AMERICA CORPORATION Bosch Group Bosch Water Heating 340 Mad River Park, Waitsfield, VT 05673 CT-13 page 2 of 2 rev 10/06 REMOVING AND CLEANING BURNERS C. Cleaning burners 1. Use a soft wire brush across burner fins to loosen any debris and then vacuum out. 2. Check to see that the 18 br ass gas injectors in the rear of t he burner assembly are clean. To access, remove 8 Philips head screws to the left and right of the two cent er brass Philips head screws at the rear of the burner. The burners should separate into two halves exposing injectors. Blow clean with compressed air or carburetor cleaner and wipe dry with cloth. Do NOT poke injectors or at tempt to clean with drill bits, wires or other objects. Clean rear venturi passages with a pipe cleaner and soapy water. Rinse clean and let dry before reinstalling. Follow instructions in reverse to reconnect bur ner halves. D. Reinstalling burners 1. Reinstall burners into burner area. 2. Reinstall set screws on right side of gas valve and tighten. 3. Reinstall right and left burner brackets with the four screws. The brass screws attach t o frame. E. Reinstalling pilot assembly and tube Models 1000P, 1600P, 260PN, 425PN: 1. Reinsert thermocouple and snap into place. Thermocouple tip should sit 1/4” above the burner bed. 2. Put spark electrode into place and attach with clip. 3. Slide upper end of pilot tube into bracket on burner assembly and reinsert pin. 4. Slide base of pilot tube to the right into clip. Ensure pilot air screen is installed between pilot tube and pilot orifice. Models 1600H, 425HN: 1. Slide pilot air screen over pilot tube. 2. Slide pilot assembly into place. Reinsert pilot shield and secure with screws to the burner assembly. F. Returning heater to service Models 1000P, 1600P, 260PN, 425PN: 1. Turn on gas and light pilot. Test for possible gas leaks where burners connect to the gas valve. Models 1600H, 425HN: 1. Turn on gas and check for leaks where the burners connect to gas valve by applying leak detecting solution as you initiate water flow to activate the heater. Allow enough time to bleed all air in gas line. Bubbles are a sign of a leak. All models: 2. If there are bubbles at either connection immediately shut off water and gas. Loosen the burner set screws on the right side of gas valve. Remove the burners and inspect the o-ring. Replace if damaged. Reseat burners and tighten set screws. Check again for leaks. 3. Replace front cover when complete. FIGURE 5 Burner fins Gas injectors Burner venturi passage Burners disassembled ©BBT NORTH AMERICA CORPORATION Bosch Group Bosch Water Heating 340 Mad River Park, Waitsfield, VT 05673 CT-14 page 1 of 1 rev 10/06 UNLOCKING THE REGULATOR MODELS: 1000P, 1600P, 1600H, 260PN, 425PN, 425HN WARNIN G ARNING LP & N G ARE EXTREMEL NG EXTREMELY FLAMMABLE Y FL AMMABLE SO UTIONS WHEN PRECAUTIONS TAKE EXTRA PRECA PERF ORMIN G ANY W ORK T O THE HEA TER PERFORMIN WORK TO HEATER If the Maxitrol regulator supplied with your water he ater is fed gas or air at too high a pressure, it will cause it to “lock up” and stop delivering gas to heater. This is the method for “unlocking” the maxitrol regulator. FIGURE 1 N ote: This procedure should only be performed by a licensed gas technician 1. Shut off main gas supply to heater. 2. Locate Maxitrol regulator at bottom of water heater. 3. Confirm that the arrow on the back of the regulator is pointing up towards the heater and in t he same direction of gas flow. If not, the regulator is installed upside down. Reinstall so that the arrow indicates the proper direction of gas flow. 4. Unscrew slot ted cap. (Fig.1) 5. The inner plug needs to be r eturned to the same spot after unlocking so count threads or measure to facilitate this. 6. Turn inner plug counter-clockwise to remove. 7. Remove spring (do not lose). 8. Use the er aser on end of pencil to push in on the diaphragm to return to unlocked position. 9. Install spring first, then install plug and turn clockwise to return to measur ed position. 10. Reinstall slot ted cap. 11. Return heater to service after correcting over pressure situation. ©BBT NORTH AMERICA CORPORATION Bosch Group gas flow slotted cap Bosch Water Heating 340 Mad River Park, Waitsfield, VT 05673 CT-21 page 1 of 1 rev 10/06 REPLACING HEAT EXCHANGER MODELS: 1000P, 1600P, 1600H, 260PN, 425PN, 425HN Removing heat exchanger 1. Remove cover as per installation manual 2. Turn off gas to heater using installer supplied shutoff valve. 3. Close installer supplied cold water shutoff valve to heater (if none installed, install before proceeding.) 4. Open lowest hot water faucet to drain lines and relieve pressure in heater. 5. Position a bucket below water connections to water heater. 6. Remove the retaining clip (Fig. 1 Num. 1) from the threaded bushing. Then remove the threaded bushing (Fig. 1 Num. 2) from the water valve. 7. Contents of heater and water lines will drain to bucket below. 8. Once all water has drained, reinsert threaded bushing into water valve and secure with retaining clip 9. Locate and remove clips on both left and right side connections on lower rear of heat exchanger. (F ig. 2, Num. 1) 10. Loosen Phillips head screw on temperature limiter (ECO) and remove from heat exchanger mount. (F ig.2, Num. 2) 11. Remove covering angle strip which runs horizontally at top of heat exchanger. (Fig. 2, Num. 3) 12. Remove heat exchanger from heater by pulling top of heat exchanger forward. When the back edge of the heat exchanger clears the draft diverter, pull heat exchanger up and out. WARNIN G ARNING LP & N G ARE EXTREMEL NG EXTREMELY FLAMMABLE Y FL AMMABLE SO UTIONS WHEN PRECAUTIONS TAKE EXTRA PRECA PERF ORMIN G ANY W ORK T O THE HEA TER PERFORMIN WORK TO HEATER FIGURE 1 FIGURE 2 Installing heat exchanger 1. Install new heat exchanger in heater. 2. Mount covering angle strip across the top of heat exchanger. (Fig. 2, pos. 3) 3. Reconnect water pipes to heat exchanger and reinstall retaining clips. NOTE: Lubricate o-rings on pipes before connecting. (Fig. 2, pos. 1) 4. Remount temperature limiter (ECO) on upper right of heat exchanger. (Fig. 2, pos. 2) 5. Turn water on and check for leaks at connections. 6. Open gas supply, replace cover and r eturn heater to service. ©BBT NORTH AMERICA CORPORATION Bosch Group Bosch Water Heating 340 Mad River Park, Waitsfield, VT 05673 CT-22 page 1 of 1 rev 08/06 CLEANING AND REPLACING PILOT ASSEMBLY MODELS: 1000P, 1600P, 1600H 260PN, 425PN, 425HN WARNIN G ARNING LP & N G ARE EXTREMEL NG EXTREMELY FLAMMABLE Y FL AMMABLE SO UTIONS WHEN PRECAUTIONS TAKE EXTRA PRECA PERF ORMIN G ANY W ORK T O THE HEA TER PERFORMIN WORK TO HEATER For 1000P, 1600P, 260PN, 425PN models: For 1600H, 425HN models: Removing pilot tube and orifice Removing pilot assembly and orifice: 1. Shut off gas to heater and remove cover per installation manual. 2. Remove wire clip holding upper end of pilot tube into burner bracket. (Fig. 1) 3. Remove lower end of pilot tube from black clip on gas valve being careful not to damage cylindrical air screen 4. Lift up pilot tube and remove from bracket 1. Shut off gas to heater and remove cover per installation manual. 2. Remove 2 philips head screws holding pilot shield and pilot assembly to front of burner. Remove pilot shield. 3. Remove pilot assembly from burners (with spark electrode and flame sensor) being careful not to damage cylindrical air screen on bottom. Cleaning pilot tube and orifice Cleaning pilot tube and orifice 1. Blow out pilot tube and air screen. 2. Remove brass hex-headed pilot orifice from gas valve with 8mm wrench. Black clip may have to be removed with pliers to access orifice with socket wrench 3. Clean orifice with compressed air or aerosol carburetor cleaner. (NOTE: Do not ream or poke any object through orifice opening). 1. Blow out pilot tube and air screen. 2. Remove brass hex-headed pilot orifice from top of pilot electrovalve with 8mm wrench. 3. Clean orifice with compressed air or aerosol carburetor cleaner. (NOTE: Do not ream or poke any object through orifice opening). Reinstalling pilot tube and orifice 1. Screw clean or new orifice into pilot electrovalve and tighten with 8mm wrench. Do not over tighten. 2. Insert pilot assembly into burner and fit cylindrical air screen onto orifice and pilot tube. 3. Insert screws through pilot shield and pilot assembly into burner and tighten. 5. Replace cover, open gas supply and return heater to service. 6. If pilot flame is not strong and blue, replace orifice (NG is stamped 2C, LP is stamped 1C). 1. Screw clean or new orifice into gas valve and tighten with 8mm wrench. Do not over tighten. 2. Place cylindrical air screen over pilot orifice. Angle top of air screen outwards. 3. Feed bottom of pilot tube into angled cylindrical air screen. Push bottom of pilot tube with air screen into black clip until it snaps into place. NOTE: Air screen may become deformed during this process. Simply mold back into cylindrical shape by hand. 4. Replace cover, open gas supply and return heater to service. 6. If pilot flame is not strong and blue, replace orifice (NG is stamped 4C, LP is stamped 3C). Reinstalling pilot assembly and orifice: FIGURE 1 FIGURE 2 Pilot wire clip Pilot shield Pilot tube Burners Pilot bracket screws Thermocouple lead Burners Pilot air screen Pilot orifice Pilot air screen Pilot orifice 1000P, 1600P, 260PN, 425PN pilot assembly ©BBT NORTH AMERICA CORPORATION Bosch Group 1600H, 425HN pilot assembly Bosch Water Heating 340 Mad River Park, Waitsfield, VT 05673 CT-23 page 1 of 2 rev 10/06 WATER VALVE REBUILD MODELS: 1000P, 1600P, 1600H 260PN, 425PN, 425HN WARNIN G ARNING LP & N G ARE EXTREMEL NG EXTREMELY FLAMMABLE Y FL AMMABLE SO UTIONS WHEN PRECAUTIONS TAKE EXTRA PRECA PERF ORMIN G ANY W ORK T O THE HEA TER PERFORMIN WORK TO HEATER A. Preparation C. Removing old parts Tools needed: Philips screwdriver Flat screwdriver Needle-nosed pliers Container to catch water 1. Remove the 5 cover screws from metal retaining plate and separate 2 halves of water valve. (Fig. 2) 2. Remove and inspect diaphragm from water valve, clean if necessary, replace if damaged or warped by excessive heat. (Fig. 3, pos. 2) 3. Remove pushrod assembly by holding water valve cover and pressing pushrod sleeve firmly against a hard surface. (Fig. 3, pos. 10) 4. Remove retaining clip and threaded bushing to access inlet water filter. Remove and clean or replace filter. (Fig. 3, pos. 6) 5. Remove retaining clip (Fig. 3, pos. 7) and volumetric flow governor. (Fig. 3, pos. 8) 6. Remove venturi from outlet port to heat exchanger. Grasp with needle-nosed pliers and twist while pulling. (Fig. 3, pos. 9) Ensure that venturi passages are clean as well as passage in water valve body. 7. If the venturi or water valve body has evidence of mineral build-up, soak in straight white vinegar for ½ hour. Brush parts clean and flush with water. 1. Shut off gas and water supply to heater. 2. Open fauce t to relieve pressure. 3. Pull off temperature adjustment knob (all models) and gas control knob(1600H, 425HN only). 4. Unscrew cover screws and remove cover. 5. Unscrew cold water supply pipe from rear of water valve and ca tch remaining water. 6. Disconnect water pipe to heat exchanger by removing retaining clip and gently pulling pipe to the right. B. Removing water valve 1. Suppor t water valve with one hand while releasing water valve from gas valve by loosening 2 set screws from underneath. (Fig. 1) Do not loosen 3 larger screws holding plate onto bottom of gas valve or 1 screw holding on microswitch. Remove water valve from heater. • If set screws do not unscrew easily do not force them as the gas valve may be damaged. Try a descaling solution (white vinegar, CLR® or other descaling solution) on screw threads. Let sit for 1 hour, try again to remove set screw(s) without forcing. • If still unable to remove, call 800-642-3111 for help. FIGURE 1 Metal retaining plate Pushrod sleeve Cover screws(5) Threaded bushing (Water filter) 2 Set screws FIGURE 2 Water Valve Water valve set screw location ©BBT NORTH AMERICA CORPORATION Bosch Group Bosch Water Heating 340 Mad River Park, Waitsfield, VT 05673 CT-23 page 2 of 2 rev 10/06 WATER VALVE REBUILD D. Rebuilding water valve F. Testing operation 1. Place diaphragm in right side of water valve, ensuring that ring on outer edge is in recess. 2. Liberally lubricate both ends of new pushrod and install pushrod assembly into water valve cover, pressing firmly in place with thumbs. (Fig. 3 pos. 10) 3. Reassemble 2 halves of water valve with metal retaining plate. Install and tighten 5 cover screws (Fig. 2). 4. Install volumetric flow governor with plug and retaining clip. Lubricate O-ring on plug befor e reinserting. 5. Lubricate O-rings on venturi and install. 6. Install inlet water filter and threaded bushing with retaining clip. Important: Before firing t he heater, r un water through heater to check for leaks and purge air. 1. Replace and tighten co ver and reinstall knob(s). 2. 1000P, 1600P, 260PN, 425PN models: light pilo t and slide control to the right to large flame position. 3. Shut off water at heater inlet and open hot water fauce t. 4. Turn temperature adjustment knob to full clockwise position. 5. Slowly open inlet water supply just until burners ignite and no fur ther. 6. Measur e water flow at open faucet to verify proper activation rate of 0.6 gallon per minute (quart in 25 seconds or gallon in 100 seconds). 7. Shut water off at heater and observe burners to verify that they go out immediately when water f low stops. E. Installing water valve 1. Remove, lubricate and reinstall water valve set screws in gas valve. Do not thread screws in fully. 1 to 2 revolutions maximum (Fig. 1). 2. Firmly seat water valve into right side of gas valve with temperature adjustment shaft facing outward (Fig. 3, pos 11). 3. Now tighten set screws fully and evenly. 4. Lubricate O-ring on pipe to heat exchanger, put into water valve and secure with retaining clip from top. 5. Reconnect cold water inlet flex pipe with washer. FIGURE 3 1. Water valve cover screws (5) 2. Water valve diaphram 3. Push rod 4. Push rod sleeve 5. Threaded bushing 6. Water filter 7. Flow governor retaining clip 8. Volumetric flow governor 9. Venturi 10. Water valve cover 11. Temper ature adjustment shaf t 4. 1. 7. 3. 10. 2. 8. 6. 11. 5. 9. ©BBT NORTH AMERICA CORPORATION Bosch Group Bosch Water Heating 340 Mad River Park, Waitsfield, VT 05673 CT-24 page 1 of 1 rev 10/06 REPLACING ECO/TEMPERATURE LIMITER MODELS: 1000P, 1600P, 1600H, 260PN, 425PN, 425HN The ECOs/temperature limiters are overheat protection sensors that will shut off all gas to the water heater in the event of overheating. Note Note: If experiencing frequent pilot outages during or just after use, first test the temperature limiter/ECO before replacing it. See Bulletin CT-02 Ther mocouple and pilot test. Tools Philips head screwdriver, pliers and 22mm or adjustable wrench Replacing lower ECO/temperature limiter (not included on model 1000P) 1. Close installer supplied cold water isolation valve to the water heater. 2. Locate the lower ECO on the ½” copper pipe exiting the bottom left side of the heat exchanger (See F ig. 1). 3. Using pliers, disconnect both spade connections to the ECO. 4. Using a 22mm or adjustable wrench, unscrew the ECO from the ½” copper pipe. Be careful not to overstrain the copper pipe. 5. Install new ECO and reconnect wires from electromagnet and flue gas sensor. Wire orientation/polarity does not mat ter when making this connection. 6. Turn on cold water supply and return the water heater to service. WARNIN G ARNING LP & N G ARE EXTREMEL NG EXTREMELY FLAMMABLE Y FL AMMABLE SO UTIONS WHEN PRECAUTIONS TAKE EXTRA PRECA PERF ORMIN G ANY W ORK T O THE HEA TER PERFORMIN WORK TO HEATER Replacing upper ECO/temperature limiter 1. Close installer supplied cold water isolation valve to the water heater. 2. Locate the upper ECO installed on the copper bend on the upper right side of the heat exchanger (Fig. 2) 3. Using pliers disconnect both spade wire connections to the ECO. 4. Remove Philips head screw from the ECO bracket. 5. Slide bracket and ECO away from the heat exchanger and separate the bracket from the ECO. Do not loose the bracket. 6. Insert new ECO into the bracket. If a new bracket is provided with the ECO, there is no need to reuse the old bracket. 7. Slide ECO and bracket onto the mounting of the heat exchanger. Heat exchanger mounting should reside between the ECO and bracket. (See Fig. 2) 8. Insert Philips head screw through ECO, heat exchanger mount and tighten into ECO bracket. 9. Reconnect wires from the flue gas sensor and the thermocouple to the ECO. Wire orientation/polarity does not mat ter when making this connection. 10. Turn on cold water supply and return water heater to service. FIGURE 2 FIGURE 1 ©BBT NORTH AMERICA CORPORATION Bosch Group Bosch Water Heating 340 Mad River Park, Waitsfield, VT 05673 CT-25 page 1 of 1 rev 10/06 REPLACING ELECTRO-MAGNET MODELS: 1000P, 1600P 260PN, 425PN WARNIN G ARNING LP & N G ARE EXTREMEL NG EXTREMELY FLAMMABLE Y FL AMMABLE SO UTIONS WHEN PRECAUTIONS TAKE EXTRA PRECA PERF ORMIN G ANY W ORK T O THE HEA TER PERFORMIN WORK TO HEATER Tools needed: FIGURE 1 8mm or small adjustable wrench 17mm or large adjus table wrench Removing Electromagnet 1. Turn off gas to the water heater. 2. Turn off water supply to the water heater using installer supplied cold water isolation valve. 3. Remove front cover of w ater heater as per instr uctions in the installation manual. 4. Using 8mm or adjus table wrench, loosen and remove 8mm nut and lead wire connected to electromagnet. 5. Using 17mm or adjustable wrench, loosen larger 17mm nut and remove electromagnet from gas valve assembly. 17mm nut 8mm nut Electromagnet location (view from bottom of heater) Installing Electromagnet 1. Insert replacement electromagnet into rear of gas valve with spring and plunger end first. 2. Secure electromagnet into gas valve by tightening large 17mm nut. Do no t over tighten. 3. Thread lead wire with 8mm nut into electromagnet and tighten. Do not over tighten. 4. Reinstall front cover per instructions in the installation manual. 5. Reopen water and gas supplie s and check for gas leaks around the electromagnet fittings. Tighten nuts further if a leak is found. 6. If no leaks are found, return heater to service. ©BBT NORTH AMERICA CORPORATION Bosch Group Bosch Water Heating 340 Mad River Park, Waitsfield, VT 05673 CT-26 page 1 of 1 rev 10/06 REPLACING ELECTRO VALVES MODELS: 1600H, 425HN WARNIN G ARNING LP & N G ARE EXTREMEL NG EXTREMELY FLAMMABLE Y FL AMMABLE SO UTIONS WHEN PRECAUTIONS TAKE EXTRA PRECA PERF ORMIN G ANY W ORK T O THE HEA TER PERFORMIN WORK TO HEATER Tools Installing electro valve Philips head screwdriver Pliers 8mm or adjustable wrenc h. Preparation This procedure should be performed by a licensed gas technician Before at tempting to replace either electro valve, turn off gas supply to the water heater and turn ON (I) /OFF (O) switch to the OFF (O) position. Removing Electrovalve 1. Locate the pilot and burner electro valves on the lower front of the water heater just to the left of the temper ature control knob and water val ve (See Fig.1). 2. Determine which electro valve is going to be replaced. The upper electro valve (orange) is r esponsible for the pilot and the lower electro val ve (green) is responsible for the burners. 3. Using pliers, disconnect wire at spade connection on electro valve needing replacement. 4. Remove the two Philips head screws on each side of the Electrovalve. 5. Remove the electro valve from the gas valve housing. Be careful not to misplace the rubber o-ring that seals the electro valve to the gas valve. If a new oring is provided with new electro valve, discard the original o-ring. NOTE: If removing the pilot electro valve, remove the pilot orif ice from the top of the electro valve by unscrewing the 8mm orifice nut with appropriate wrench (See Fig. 1). Do not lose the pilot orif ice. ©BBT NORTH AMERICA CORPORATION Bosch Group 1. If installing the pilot electro valve, insert and tighten the pilot orifice nut from the old valve into the top of the new pilot Electrovalve. 2. Inser t the rubber o-ring into the groove of the electro valve housing on the gas valve. Failure to do this may result in a gas leak. 3. Insert electro valve into the electro valve housing on the gas valve making sure to align the screw holes between the two. 4. Reconnect wire fr om the electronic control box to the electro v alve. 5. Turn on the gas supply to the water heater and chekc for ga s leaks. 6. Return the heater to ser vice. If the unit does not ignite at first, try cycling the water off and on to make sure that air has been sufficiently bled from the gas line. Note: It may take several cycling attempts to purge all the air out. FIGURE 1 Pilot electro valve Burner electro valve Bosch Water Heating 340 Mad River Park, Waitsfield, VT 05673 CT-27 page 1 of 1 rev 10/06 REPLACING CONTROL BOX MODELS: WARNIN G ARNING 1600H, 425HN LP & N G ARE EXTREMEL NG EXTREMELY FLAMMABLE Y FL AMMABLE SO UTIONS WHEN PRECAUTIONS TAKE EXTRA PRECA PERF ORMIN G ANY W ORK T O THE HEA TER PERFORMIN WORK TO HEATER Tools FIGURE 1 Philips head screwdriver, needle-nosed pliers. Removing Ignition Unit 1. Close installer supplied cold water isolation valve to water heater. 2. Remove front cover of heater a s per instructions in the installation manual. 3. Remove single ignition wir e connection (to spark electrode) from upper left corner of ignition unit. Unclip wire from br acket on top of ignition unit (425HN models only). (See F ig. 1) 4. Remove multiple wire connector from lower right corner of ignition unit by gently pulling outwards with needle-nosed pliers. (See Fig. 1) 5. Remove scr ew with ground wire connection from upper right corner of ignition unit. Metal bracket and ignition unit will drop down out of heater. 6. Remove ignition unit fr om metal bracket. Control box 1600H, 425HN control box location Installing Ignition 1. Inser t tab on lower left of ignition unit into slot in lower left of bracket. 2. Mount ignition unit with br acket to heater by inser ting screw into upper right hand cor ner. Note: feed screw through ground wire e yelet with washer before threading through ignition unit to heater. (See Fig. 1) 3. Press multiple wire connector into lower right of ignition unit. 4. Push ignition wire into single terminal in top left corner of ignition unit. Clip wire into bracket on top of ignition unit (425HN models only). 5. Install front cover, open cold water supply and return heater to service. ©BBT NORTH AMERICA CORPORATION Bosch Group Bosch Water Heating 340 Mad River Park, Waitsfield, VT 05673 CT-28 page 1 of 1 rev 10/06 REPLACING THERMOCOUPLE AND FLUE SENSOR MODELS: 1000P, 1600P 260PN, 425PN WARNIN G ARNING LP & N G ARE EXTREMEL NG EXTREMELY FLAMMABLE Y FL AMMABLE SO UTIONS WHEN PRECAUTIONS TAKE EXTRA PRECA PERF ORMIN G ANY W ORK T O THE HEA TER PERFORMIN WORK TO HEATER Tools needed: FIGURE 1 Pliers, 8mm or adjustable wrench Removing thermocouple and flue sensor 1. Turn off gas supply to the water heater. 2. Tur n off water supply into the water he ater using installer supplie d cold water isola tion valve. 3. Remove front cover as per instr uctions in the installation manual. 4. The t hermocouple is located in the center of the burner rows directly behind the white ceramic spark electrode. Carefully, push down on the top on the thermocouple wit h a flat head screw driver until it clicks out of bracket. Pull down on thermocouple wires until it is free from burner bracket. (Fig. 1). 5. Loosen and remove onl y the 8mm brass nut from electromagnet on rear of gas valve. (Fig. 2) 6. Disconnect wire from thermocouple at the lo wer temperature limiter (ECO). (F ig. 2) 7. Disconnect wire from the flue gas sensor at the upper temperature limiter (ECO). (F ig. 3) 8. Remove Philips head screw at taching the flue gas sensor to the draft hood. (Fig. 3) 9. Remove thermocouple & flue gas sensor with wires from heater. Installing thermocouple and flue sensor N ote : Replacement parts will come as two separate parts. At tach the thermocouple to the safety circuit wiring with the quick connect plug before proceeding. 1. Attach flue gas sensor to the upper right hand side of the draft hood using Philips head screw. Flue gas sensor should be on the inside of the draft hood in order to proper ly sense flue gas spillage. (F ig. 3) 2. Connect wire connection at upper temperature limiter (ECO). (Fig. 3) 3. Feed wires down the right hand side of the water heater and secure in wire tie on the lower right side of heater chassis. Make sure that none of the wires rest against the copper heat exchanger. 4. Connect wire connection from thermocouple to lower temperature limiter (ECO). (F ig. 2) 5. Feed replacement thermocouple from underneath burners into burner bracket. Push into bracket until it snaps in place. (Fig. 1) 6. Thread 8mm nut end from flue sensor wire into elecver tight en. tromagnet and tighten. Note : Do no nott o ov 7. Reinstall heater cover as per instructions in the installation manual. 8. Reopen water and gas supplies and return heater to ser vice. ©BBT NORTH AMERICA CORPORATION Bosch Group Thermocouple tip (press down) Thermocouple location FIGURE 2 8mm nut Lead from upper ECO Lead from thermocouple Lower temperature limiter Electromagnet Location (view from bottom of heater) FIGURE 3 Flue gas sensor Lead from flue gas sensor Upper temperature limiter Flue sensor Location (view from right side of heater) Bosch Water Heating 340 Mad River Park, Waitsfield, VT 05673 BBT North America Corporation Bosch Group Bosch Water Heating 340 Mad River Park Waitsfield, VT 05673 Telephone 800-642-3111 Fax (802) 496-6924 www.protankless.com [email protected]