® TTW Eco-Defender Residential Ultra Low NOx Gas Water Heaters SERVICE MANUAL Troubleshooting Guide and Instructions for Service (To be performed ONLY by qualified service providers) Models Covered by This Manual: U1TW40S*FRN U1TW50S*FRN U1TW60T*FRN U4TW40T*FRN U4TW50T*FRN U4TW60T*FRN U2TW50T*FRN U2TW65T*FRN UTW450S60FR*N UTW465S60FR*N (*) Denotes Warranty Years (Model Shown: U-4-TW-40T6FRN) Manual 238-48509-00A Save this manual for future reference
Table of Contents Section Page Introduction ______________________________________________5 How to Use this Manual _____________________________________6 Tools Required for Service ___________________________________7 Specifications _____________________________________________8 Sequence of Operation_____________________________________ 12 Power Up Sequence Normal Heating Sequence Abnormal Operation Troubleshooting __________________________________________ 17 Burner Maintenance __________________________
WARNING If the information in these instructions is not followed exactly, a fire or explosion may result causing property damage, personal injury, or death. What to do if you smell gas: x Do not try to light any appliance x Do not touch any electrical switch; do not use any phone in your building x Immediately call your gas supplier from a neighbor’s phone. Follow the gas supplier’s instructions. x If you cannot reach your gas supplier, call the fire department.
WARNING Water heaters are heat producing appliances. To avoid damage or injury, do not store materials against the water heater or any of its components. Use proper care to avoid unnecessary contact, especially by children, with the water heater and its components. Under no circumstances must flammable materials, such as gasoline or paint thinner be used or stored in the vicinity of this water heater or in any location in which the fumes could reach the water heater.
Introduction The Bradford White ECO-DEFENDER Safety System® The Bradford White ECO-DEFENDER Safety System was designed to resist the ignition of flammable vapors that can occur outside of the water heater and produce Ultra Low NOx emissions. Use and installation are nearly identical to previous versions of atmospherically fired and vented water heaters. A number of exclusive design features are incorporated in the system that will require additional knowledge on the part of the qualified service provider.
How to Use this Manual operating parameters exists, the gas control diagnostic LED will flash a code to positively identify an operational issue. This service manual is designed to facilitate problem diagnosis and enhance service efficiency. To further promote quicker service times the new gas valve can be removed and replaced without draining the water heater. A special tool is required and will be provided with each gas valve kit shipped from our Service Parts department.
Tools Required Contact the Bradford White technical support group immediately if diagnosis cannot be made using the methods described in this service manual. Tools Required for Service Manometer: A liquid “U” tube type or a digital (magna-helic) type can be used. This device is used to measure gas and/or air pressure and vacuum. Multi-Meter: A digital type is strongly recommended. This device is used to measure electrical values.
Specifications Power Supply Dedicated 115VAC, 60 Hz, 15A. Gas Supply Pipe Minimum 1/2” NPT (schedule 40 black iron pipe recommended). Approved Gas Type Natural Gas. Gas Pressure 6.0” W.C. minimum, 11.0” W.C. maximum. Venting System Power vent through the wall or vertical through the roof. Approved Vent Materials PVC, CPVC or ABS. Minimum clearance for Servicing 18” from top, 24” from front, 4” sides and rear. Water Supply Pressure 150 PSI maximum allowable working pressure.
Specifications Vent Tables Venting Specifications for: 40 Gallon 50 Gallon 60 Gallon 2” Diameter (5.1 cm) PVC Vent Connector Lengths Terminating # of Elbows Maximum Straight Length ft (m) Minimum Straight Length ft (m) Through the Wall 1 45 (13.7) 2 (0.6) Through the Wall 2 40 (12.2) 2 (0.6) Through the Wall 3 35 (10.7) 2 (0.6) Through the Wall 4 30 (9.2) 2 (0.6) Through the Roof 0 50 (15.2) 7 (2.1) Through the Roof 1 45 (13.7) 7 (2.1) Through the Roof 2 40 (12.2) 7 (2.
Specifications Vent Tables Venting Specifications for: 48 Gallon 65 Gallon 3” Diameter (7.6 cm) PVC Vent Connector Lengths Terminating # of Elbows Maximum Straight Length ft (m) Minimum Straight Length ft (m) Through the Wall 1 55 (16.8) 2 (0.6) Through the Wall 2 50 (15.2) 2 (0.6) Through the Wall 3 45 (13.7) 2 (0.6) Through the Wall 4 40 (12.2) 2 (0.6) Through the Roof 0 60 (18.3) 7 (2.1) Through the Roof 1 55 (16.8) 7 (2.1) Through the Roof 2 50 (15.2) 7 (2.
Specifications Control Timings Ignition State Timing Pre-purge 15 seconds Trial for Ignition 90 seconds Flame Stabilization Period 3 seconds Inter-purge 15 seconds Flame Failure Response Time 1.
Sequence of Operation Power Up Sequence 1. Start-up: Upon power up, the gas control runs a safe start check with a typical delay of 5 seconds. 2. Flammable Vapor Verification: The gas control verifies that the Flammable Vapor Sensor is in the proper operating range prior to energizing any components. If the sensor is within the proper range, the gas control resumes normal operation. If the Flammable Vapor Sensor is out of range, the gas control LED immediately flashes 7 times with a 3 second pause.
Sequence of Operation Normal Heating Sequence (cont’d) 7. Main Burner Ignition: After pilot flame is sensed, the gas control activates the main valve for main burner ignition. The gas control will ignore flame and pressure switch signals for 3 seconds to allow for the main burner to stabilize. 8.
Sequence of Operation Abnormal Operation (cont’d) B) If the resistance is below 3000 ohms: The gas control immediately turns off all outputs and proceeds to flash 8 times then 1 time with a three second pause. The error self clears if the resistance returns to normal range for at least 15 seconds. 2. Temperature Sensor Fault: A) Temperature Sensor Open Circuit: The gas control immediately turns off all outputs and proceeds to flash 8 times then 3 times with a three second pause.
Sequence of Operation Abnormal Operation (cont’d) B) Pressure switch or blower temperature switch failed to close: The gas control runs the blower for 30 seconds waiting for the pressure switch and/or the blower temperature switch to close. If either switch does not close in 30 seconds, the blower turns off and the control flashes 3 times with a 3 second pause. The gas control waits 2 minutes before turning on the blower for another 30 seconds to see the circuit close.
Sequence of Operation Abnormal Operation (cont’d) 5. Flame Sensing Fault: A) Flame Lost During Run: The gas control turns off the pilot and main valves and runs the blower for 15 seconds (inter-purge) The gas control increments the recycle count, if the recycle count has not reached its limit (4), another trial for ignition begins. If the recycle count has been reached, the gas control LED flashes 6 times then 3 times with a 3 second pause.
Troubleshooting Observe the green LED on the water heater gas control. Error codes are displayed with a 3 second pause before repeating. Once the error code is known, check and repair the water heater, as recommended in the table below.
Troubleshooting LED Status Control Status Six flashes, one flash, Failed to light pilot, three second system resets after pause (Soft (5) minutes Lockout) Pressure switch or Six flashes, blower temperature two flashes, switch opened three second during burner pause (Soft operation. System Lockout) resets after (5) minutes Six flashes, three Pilot flame flashes, extinguished, three second system auto resets pause (Soft after (5) minutes Lockout) Probable Cause 1. Unstable pilot 2.
Troubleshooting LED Status Control Status Probable Cause Service Procedure 1. Damage to thermal well wires 2. Thermal well sensor resistance Thermal well sensor out of range Eight flashes, 3. Replace thermal well damaged or unSee Thermal Well Testing on three flashes, plugged or gas con- 4. Verify control is not wet or page 34 three second trol electronics fault physically damaged pause 5. Reset control on/off switch detected 6.
Burner Maintenance Burner Inspection At periodic intervals (every 6 months), a visual inspection should be made of the pilot and main burner for proper operation and to assure no debris is accumulating. The pilot flame should be stable. Some causes for an unstable pilot flame are: a) Gas pressure is out of specification. b) Pilot flame not fully engulfing spark/flame sensor. The main burner should light smoothly from the pilot and burn with a blue flame with a minimum of yellow tips.
Burner Maintenance Burner Cleaning Procedure (cont’d) Step 5. Remove the (4) 1/4” hex drive screws holding the right side inner door in place. (4) 1/4” hex drive screws Right side inner door Step 6. Remove the (3) 1/4” hex drive screws holding the left side burner door in place. (3) 1/4” hex drive screws Left side burner door Step 7. Disconnect the pilot tube using a 7/16” wrench and the main burner feedline with a 3/4” wrench from the gas control. Pilot and main feedlines Step 8.
Pilot Maintenance Burner Cleaning Procedure (cont’d) Step 11. Thoroughly inspect burner screen and burner venturi and remove any loose debris accumulation. Inspect burner screen for any openings larger Burner screen than the normal screen openings. Step 12. Use compressed air and/or a vacuum to remove any scale or other debris accumulation from the burner screen and venturi. Burner venturi Step 13. Disconnect (unscrew) manifold mount from feed line.
Pilot Maintenance Pilot Inspection, Testing and Replacement (cont’d) Step 2. Unplug the water heater from the wall outlet. TTW (water heater) power cord Step 3. Turn off the gas supply to the water heater. Step 4. Remove the outer door. Outer Door Step 5. Remove the (4) 1/4” hex drive screws holding the right side inner door in place. (4) 1/4” hex drive screws Right side inner door Step 6.
Pilot Maintenance Pilot Inspection, Testing and Replacement (cont’d) Step 8. Remove the burner assembly from the combustion chamber. Burner assembly Step 9. Remove the pilot assembly from the main feedline using a 1/4" nut driver. Pilot assembly 1/4” nut driver Step 10. Visually inspect the spark igniter/flame sense wire for damage. Replace the pilot assembly, if damage is found. Step 11. With a multi-meter set to the ohms setting, check continuity through the spark igniter/flame sense wire.
Pressure Switch Testing Pilot Inspection, Testing and Replacement (cont’d) Step 15. Inspect the pilot tubing and pilot orifice for blockages: a) Remove ferrule nut from the bottom of the pilot assembly using a 7/16" wrench. b) Remove the pilot tube and pilot orifice. c) Inspect the pilot tubing and pilot orifice for blockages. Clean or replace, as necessary. Step 16. Reassemble the pilot assembly and install it on the main burner. Reinstall the burner assembly into the combustion chamber.
Pressure Switch Testing Pressure Switch Testing (cont’d) Pressure switch wire leads With steps 1,2 & 3 complete, disconnect wire leads from pressure switch. Use a multi-meter set to the ohms setting. With blower off, check across the pressure switch terminals. Are the switch contacts open (no electrical continuity)? Check the tubing and pressure tap on switch for blockage. Is there a blockage? N Y Y Y N Check the tubing and pressure tap on switch for blockage.
Pressure Switch Replacement Pressure Switch Replacement WARNING 115 volt potential exposure. Use caution making voltage checks to avoid personal injury. Step 1. Move the gas control power switch to the “OFF” position. Gas control power switch Step 2. Remove the three screws (Phillips screw driver) from the control access cover on the blower assembly and remove cover. Control access cover Step 3. Carefully blower housing.
Blower Testing Step 5. Disconnect yellow wires from the pressure switch. Yellow pressure switch wires Step 6. Reconnect wires from step 5 to new pressure switch. Step 7. Reconnect tubing to new pressure switch. Step 8. Carefully position pressure switch into blower housing. Step 9. Position gas control power switch to the “ON” postion and verify proper heater operation. Step 10. Replace control access cover form step 2. Blower Testing WARNING 115 volt potential exposure.
Blower Replacement Blower Removal Step 1. Move the gas control power switch to the “OFF” position. Gas control power switch Step 2. let. Unplug the water heater from the wall outTTW (water heater) power cord Step 3. Disconnect vent system from exhaust adapter on top of blower. Remove exhaust adapter and retain for use on new blower Step 4. Remove exhaust adapter from blower (blade screw driver) and retain for use on new blower. Blower mounting screws Step 5.
Blower Temperature Switch Testing Blower Installation (cont’d) Step 11. Secure blower in place using mounting screws from step 7. Step 12. Reinstall exhaust adapter from step 4. Step 13. Reinstall dilution air clip from step 5. Step 14. Reconnect vent system to exhaust adapter. Step 15. Reconnect cords from step 6. Step 16. Position gas control power switch to the “ON” position. Step 17. Verify proper blower operation. Blower Temperature Switch Testing WARNING 115 volt potential exposure.
Blower Temperature Switch Testing Blower Temperature Switch Testing (cont’d) Switch Setting Opens on rise @ approximately 165oF Auto resets on fall @ approximately 160oF Cool switch to below 160oF Disconnect wire leads to switch. Using multi-meter set to the ohms setting. Is there continuity between the switch terminals? N Replace switch (see page 33). Common causes for high exhaust temperature Y 1. Vent length is below minimum allowable 2. Vent diameter not to specification 3.
Blower Temperature Switch Replacement Blower Temperature Switch Replacement WARNING 115 volt potential exposure. Use caution making voltage checks to avoid personal injury. Step 1. Move the gas control power switch to the “OFF” position. Gas control power switch Step 2. Remove the three screws (Phillips screw driver) from the control access cover on the blower assembly and remove cover. Control access cover Step 3. Locate blower temperature switch. Step 4.
Thermal Well Testing Thermal Well Testing CAUTION Do not use standard multi-meter probes for this testing. Doing so will damage the connector. Use special pin type electronic probes or small diameter wire pins inserted into connector. Follow the procedure, below, if the water heater gas control has gone into a ECO lockout (4 flash, 3 second pause). Reset the gas control by rotating the setpoint knob to the minimum setting for at least 6 seconds before returning to the desired water temperature setting.
Determine Tank Temperature Thermal Well Testing (cont’d) Determine the correct resistance values using the Determine the Water Temperature Inside the Tank procedure on page 23. If the values are correct, replace the gas control, otherwise replace the thermal well. Determine Water Temperature Inside Tank WARNING Stored water may be HOT when performing the following steps in this procedure. Take necessary precaution to prevent personal injury.
Component Disassembly Sensor Resistance at Various Temperatures °F 40 50 60 70 80 90 100 110 120 130 140 150 160 170 180 190 200 0 26109 19906 15314 11884 9299 7333 5827 4663 3758 3048 2488 2043 1688 1402 1170 982 828 1 25400 19383 14925 11592 9078 7165 5697 4562 3679 2986 2439 2004 1656 1376 1150 965 814 2 24712 18876 14548 11308 8862 7000 5570 4464 3602 2925 2391 1966 1625 1351 1129 949 801 3 24045 18383 14180 11032 8653 6839 5446 4368 3527 2866 2344 1928 1595 1327 1110 933 788 In Degrees 4 23399 179
Gas Control Removal Gas Control & Thermal Well Removal From Water Heater (cont’d) Step 4. Disconnect the pilot tube using a 7/16” wrench and the main burner feedline with a 3/4” wrench from the gas control. Pilot and main feedlines Step 5. Disconnect the wire harnesses and spark igniter/ flame sense wire from the gas control. Gas control Spark igniter/flame sensor wire Step 6. Remove the gas control & thermal well by rotating the flats of the Thermal Well counter clockwise using a 1-5/16” wrench.
Gas Control Assembly Gas Control Removal From Thermal Well (cont’d) Step 3. Turn off the gas supply to the water heater and disconnect the gas piping from the gas control. Step 4. Disconnect the pilot tube using a 7/16” wrench and the main burner feedline with a 3/4” wrench from the gas control. Pilot and main feedlines Step 5. Disconnect the wire harnesses and spark igniter/ flame sense wire from the gas control. Gas control Spark igniter/flame sensor wire Step 6.
Gas Control Assembly Gas Control Assembly to the Thermal Well (cont’d) Step 2. Route the wire leads back into relief opening. Wire leads on thermal well Slots in thermal well Relief opening Step 3. Align the slots located on the thermal well flange with the tabs located on the back of the gas control. Tabs on back of gas control Step 4. Carefully push the gas control back onto the thermal well flange as far as possible towards the water heater. Then, slide the gas control down to lock into position.
Flammable Vapor Sensor Testing Gas Control Assembly to the Thermal Well (cont’d) Step 8. To resume operation, follow the instructions located on the water heater lighting instruction label. Or, use the lighting instructions located in the water heater installation and operating manual. Flammable Vapor Sensor Testing CAUTION Do not use standard multi-meter probes for this testing. Doing so will damage the connector. Use special pin type electronic probes or small diameter wire pins inserted into connector.
115 VAC Circuit Trace WARNING 115 volt potential exposure. Use caution making voltage checks to avoid personal injury. LED status: None, control LED not on or flashing. Disconnect cord set as shown in photo 9. LED status: Short flash once every four seconds. LED status: “Heartbeat”, alternates bright/dim. Waiting for call for heat. Thermostat calling for heat. 9 Using a volt meter set to volts AC, is there 115VAC across terminals shown in photo 10? Verify error code as listed on page 17.
Safety Circuit Voltage Trace WARNING 115 volt potential exposure. Use caution making voltage checks to avoid personal injury. Safety Circuit Voltage Trace 14 Note: This procedure assumes a cold tank. Step 1. Remove three screws (Phillips screw driver) from control access cover on blower and remove Control access cover cover. Position gas control switch to the “ON” position and adjust the thermostat dial to call for heat.
Blower Removal Remove the Blower to Gain Access to the Flue Baffle Step 1. Move the gas control switch to the “OFF” position. Step 2. Unplug from the wall outlet. the water Gas control power switch TTW (water heater) power cord power heater Exhaust adapter Blower mounting screws Step 3. Disconnect the vent system from the exhaust adapter on top of blower. Step 4. blower. Unplug the cord sets from the Blower cord sets Step 5. Remove the three blower mounting screws (1/4” nut driver). Step 6.
Dip Tube Inspection water heater. Remove the Blower to Gain Access to the Flue Baffle (cont’d) Step 8. Inspect the baffle for deterioration and missing restrictors. Clean any scale or debris build-up. Replace with a new baffle, as necessary. Step 9. Reinstall the baffle into the flue. Be sure the baffle hanger tab is inserted into the notch locations at the top of the flue. Step 10. Check the burner to ensure no scale has accumulated during operation.
Anode Inspection be free of cracks and any blockage. Hydro-jet slots should be open and free of any blockage. Any damage, such as cracks, restriction due to deformation, or unintentional holes are not field repairable and the inlet nipple/diptube must be replaced. Step 7. Upon completion of the inspection or subsequent replacement, reinstall the inlet nipple/diptube into the water heater. Connect the nipple to the plumbing system, resume water supply to the water heater, and refill the water heater.
Inner Door Removal Step 8. To resume operation, follow the instructions located on the water heater lighting instruction label. Or, use the lighting instructions located in the water heater installation and operating manual. Inner Door Removal Procedure Step 1. sition. Gas control power switch Move the gas control power switch to the “OFF” po- Blower (water heater) power cord Step 2. Unplug the water heater from the wall outlet. Outer door Step 3. Remove the outer door.
Inner Door Gasket Replacement Step 6. Remove the connectors attached to the resettable thermal switch on the manifold mount. Flammable vapor sensor clip Inner Door Removal Procedure (cont’d) Step 7. Remove the flammable vapor sensor from the clip by pushing down on the tab to open the clip. Flammable vapor sensor Step 8.
Inner Door Installation inner door gasket to the inner door sections. Refer to the illustration for proper applica- WARNING Stripped fastener connections may allow for an inner door seal breach. A seal breach may result in a fire or explosion, causing property damage, personal injury, or death. Do not over tighten screws. If a fastener connection is stripped, contact the manufacturer listed on the water heater rating plate. tion. Note the overlap configuration in the flange area of the inner door.
Arrestor Cleaning screws. Verify that both the left and right side inner doors are properly positioned and sealed against the combustion chamber. Step 8. Re-install the outer door. Step 9. To resume operation, follow the instructions located on the water heater lighting instruction label. Or, use the lighting instructions located in the water heater installation and operating manual. ScreenLok® Flame Arrestor Cleaning Procedure Step 1.
Common Terms Common Terms BTU British Thermal Units ECO Energy Cut Off GPM Gallons per Minute Hz Hertz KWh Kilowatts per hour LED Light Emitting Diode NPT National Pipe Thread Ohms Ohms of resistance PSI Pounds per Square Inch RPM Revolutions per Minute VAC Volts Alternating Current W.C.
Parts List 2 40 9 12 10 13 3 11 1 4 14 5 7 6 28 27 15 33 26 32 23 25 20 30 34 31 35 21 36 24 22 16 37 19 38 18 18 39 17 18 18 18 29 29 Part Name and Description 1. Blower Complete 15. T&P Valve 29. Burner Assembly 2. Air Mixing Inlet 16. Outer Door 30. Flexible Gas Feedline 3. Pressure Switch 17. Right Side Inner Door 31. Thermal Switch 4. Blower Temperature Switch 18. Screw #10-12 x 3/4” 32. Screw #8-18 x 1/2” 5. Blower Gasket 19. Brass Drain Valve 33. Burner 6.
Email parts@bradfordwhite.com techserv@bradfordwhite.com www.bradfordwhite.
