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Residential Ultra Low NOx Gas Water Heaters
Manual 238-48385-00A
TTW Eco-Defender
®
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
U2TW50T*FRN
U2TW65T*FRN
UTW450S60FR*N
UTW465S60FR*N
(*) Denotes Warranty Years
Save this manual for future reference
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Table of Contents
Related Manuals for Bradford White TTW ECO-DEFENDER U1TW40S*FRN
Summary of Contents for Bradford White TTW ECO-DEFENDER U1TW40S*FRN
- Page 1 TTW Eco-Defender Residential Ultra Low NOx Gas Water Heaters Manual 238-48385-00A ® 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 U2TW50T*FRN U2TW65T*FRN UTW450S60FR*N UTW465S60FR*N (*) Denotes Warranty Years Save this manual for future reference...
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Page 2: Table Of Contents
Section 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 _______________________________________ 20 Burner Inspection Burner Cleaning Procedure Pilot Maintenance _________________________________________ 22 Pilot Inspection Testing and Replacement Pressure Switch Testing and Replacement _____________________ 25... - Page 3 Do not store or use gasoline or other flammable, combustible, or corrosive vapors and liquids in the vicinity of this or any other appliance. Incorrect operation of this water heater may create a hazard to life and property and will nullify the warranty.
- Page 4 Under no circumstances must flam- mable 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.
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Page 5: 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 iden- tical to previous versions of atmospherically fired and vented water heaters. -
Page 6: How To Use This Manual
To further promote quicker service times the new gas valve can be removed and replaced with- out draining the water heater. A special tool is required and will be provided with each gas valve kit shipped from our Service Parts department. -
Page 7: Tools Required For Service
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. -
Page 8: Specifications
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 Venting System Power vent through the wall or vertical through the roof. Approved Vent Materials PVC, CPVC or ABS. -
Page 9: Vent Tables
Venting Specifications for: 40 Gallon—40,000 BTU/hr. 50 Gallon—40,000 BTU/hr. 60 Gallon—42,000 BTU/hr. 2” Diameter (5.1 cm) PVC Vent Connector Lengths Terminating # of Elbows Through the Wall Through the Wall Through the Wall Through the Wall Through the Roof Through the Roof Through the Roof Through the Roof Through the Roof... - Page 10 Specifications Venting Specifications for: 48 Gallon—60,000 BTU/hr. 65 Gallon—60,000 BTU/hr. 3” Diameter (7.6 cm) PVC Vent Connector Lengths Terminating Through the Wall Through the Wall Through the Wall Through the Wall Through the Roof Through the Roof Through the Roof Through the Roof 4”...
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Page 11: Control Timings
Ignition State Pre-purge Trial for Ignition Flame Stabilization Period Inter-purge Flame Failure Response Time Post-purge PS Fault Delay (failed open/close) Soft Lockout TCO Limit Lockout Verify Resistive Delay Simulated Resistive Load Lockout Hardware Error Lockout BLOWER PILOT Honeywell RESETTABLE THERMAL Control Timings Timing 15 seconds... -
Page 12: Sequence Of Operation
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 Flamma- ble Vapor Sensor is in the proper operating range prior to energizing any components. -
Page 13: Abnormal Operation
Normal Heating Sequence (cont’d) 7. Main Burner Ignition: After pilot flame is sensed, the gas control acti- vates the main valve for main burner ignition. The gas control will ig- nore flame and pressure switch signals for 3 seconds to allow for the main burner to stabilize. - Page 14 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 nor- mal range for at least 15 seconds.
- Page 15 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.
- Page 16 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.
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Page 17: Troubleshooting
Observe the green LED on the water heater gas con- trol. 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. - Page 18 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.
- Page 19 LED Status Control Status Thermal well sensor Eight flashes, damaged or un- three flashes, plugged or gas con- three second trol electronics fault pause detected Eight flashes, four flashes, Gas control fault three second detected pause Troubleshooting Probable Cause 1. Damage to thermal well wires 2.
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Page 20: Burner Maintenance
(see burner cleaning procedure below). Burner Cleaning Procedure Step 1. Move the gas control power switch to the “OFF” position. Step 2. Unplug the water heater from the wall outlet. Step 3. Turn off the gas supply to the water heater. Step 4. - Page 21 Burner Cleaning Procedure (cont’d) Step 5. Remove the (4) 1/4” hex drive screws holding the right side inner door in place. Step 6. Remove the (3) 1/4” hex drive screws holding the left side burner door in place. Step 7. Disconnect the pilot tube using a 7/16”...
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Page 22: Pilot Maintenance
Restore gas supply and check for gas leaks. Step 16. To resume operation, follow the instructions located on the wa- ter heater lighting instruction label. Or, use the lighting instructions located in the water heater installation and operating manual. Pilot Inspection, Testing and Replacement Step 1. Move power switch to the “OFF”... - Page 23 Pilot Inspection, Testing and Replacement (cont’d) Step 2. Unplug the water heater from the wall outlet. Step 3. Turn off the gas supply to the water heater. Step 4. Remove the outer door. Step 5. Remove the (4) 1/4” hex drive screws holding the right side inner door in place.
- Page 24 Pilot Maintenance Pilot Inspection, Testing and Replacement (cont’d) Step 8. Remove the burner assembly from the com- bustion chamber. Step 9. Remove the pilot assembly from the main feedline using a 1/4" nut driver. Step 10. Visually inspect the spark igniter/flame sense wire for damage. Replace the pilot assembly, if damage is found.
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Page 25: Pilot Inspection Testing And Replacement
To resume operation, follow the instructions located on the wa- ter heater lighting instruction label. Or, use the lighting instructions located in the water heater installation and operating manual. Pressure Switch Testing 115 volt potential exposure. Use caution making voltage checks to avoid Step 1. - Page 26 Pressure Switch Testing Pressure Switch Testing (cont’d) With steps 1,2 & 3 complete, discon- nect wire leads from pressure switch. Use a multi-meter set to the ohms setting. With blower off, check across the pres- sure switch termi- nals. Are the switch contacts open (no electrical continuity)?
- Page 27 Pressure Switch Replacement 115 volt potential exposure. Use caution making voltage checks to avoid Step 1. Move the gas control power switch to the “OFF” position. Step 2. Remove the three screws (Phillips screw driver) from the control access cover on the blower as- sembly and remove cover.
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Page 28: Blower Testing And Replacement
Blower Testing Step 5. Disconnect yellow wires from the pres- sure switch. 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. - Page 29 Blower Testing (cont’d) Does blower Disconnect pres- energize within sure switch tub- 2 minutes? ing from blower (see photo 3). Pressure tap. Pressure switch tubing Does blower energize after See pressure 2 minutes, run switch testing for 30 seconds on page 25. and shut down? Disconnect...
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Page 30: Vent System
Step 6. Unplug cord sets from blower. Step 7. Remove mounting screws (1/4” nut driver). Step 8. Remove blower with gasket from water heater. Blower Installation Step 9. Clean any debris from jacket head of water heater Step 10. Set new blower with gasket in place using locating pins on blower flange to line up with location holes in jacket head. -
Page 31: Blower Temperature Switch Testing And Replacement
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. - Page 32 Blower Temperature Switch Testing Blower Temperature Switch Testing (cont’d) Switch Setting Opens on rise @ approximately 165 Auto resets on fall @ approximately 160 Cool switch to below 160 Disconnect wire leads to switch. Using multi-meter set to the ohms setting. Is there continuity between the switch terminals? Reconnect wire leads and ob-...
- Page 33 Blower Temperature Switch Replacement Blower Temperature Switch Replacement 115 volt potential exposure. Use caution making voltage checks to avoid Step 1. Move the gas control power switch to the “OFF” position. Step 2. Remove the three screws (Phillips screw driver) from the control access cover on the blower as- sembly and remove cover.
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Page 34: Thermal Well Testing
Follow the procedure, below, if the water heater gas control has gone into a ECO lock- out (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 tem- perature setting. -
Page 35: Determine Water Temperature Inside Tank
Thermal Well Testing Procedure on page 21, water flow through the water heater should not occur. Prior to performing the steps below, turn off the cold water supply to the water heater. This will prevent cold water flow into the tank affect- ing the resistance value of thermal well. -
Page 36: Component Disassembly
Step 3. Drain the water heater to a point below the gas control level. Step 4. Turn off the gas supply to the water heater and disconnect the gas piping from the gas control. Page 36 In Degrees F 24712... -
Page 37: 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. Step 5. Disconnect the wire harnesses and spark igniter/ flame sense wire from the gas control. -
Page 38: Gas Control Assembly
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”... - Page 39 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 posi- tion. Step 5.
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Page 40: Flammable Vapor Sensor Testing And Replacement
115 VAC Circuit Trace Step 1. Verify 115VAC and proper polarity are at the wall outlet. Step 2. With the water heater plugged in and the gas control power switch in the “ON” position verify LED status. Page 40 CAUTION... -
Page 41: Vac Circuit Trace
115 volt potential exposure. Use caution making voltage checks to avoid LED status: None, control LED not on or once every four flashing. Waiting for call Disconnect cord set as shown in photo 9. Using a volt meter set to volts AC, is there 115VAC across terminals shown in photo 10? -
Page 42: Safety Circuit Voltage Trace
Safety Circuit Voltage Trace 115 volt potential exposure. Use caution making voltage checks to avoid Safety Circuit Voltage Trace Note: This procedure assumes a cold tank. Step 1. Remove three screws (Phillips screw driver) from control access cover on blower and remove Position gas control switch to the “ON”... -
Page 43: Blower Removal
Step 5. Remove the three blower mounting screws (1/4” nut driver). Step 6. Remove the blower with gasket from the top of the water heater. Step 7. Remove the flue baffle from the Gas control power p o w e r... -
Page 44: Diptube Inspection And Replacement
Step 15. To resume operation, follow the instructions located on the water heater Water heater components and stored water may be HOT when performing the following steps in this procedure. Take necessary precaution to prevent personal injury. lighting instruction label. Or, use the lighting instructions located in the water heater installation and operating manual. -
Page 45: Anode Inspection And Replacement
Step 8. To resume operation, follow the instructions located on the water heater Water heater components and stored water may be HOT when performing the following steps in this procedure. Take necessary precaution to prevent personal injury. lighting instruction label. Or, use the lighting instructions located in the water heater installation and operating manual. -
Page 46: Inner Door Removal, Inspection And Replacement
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. Move the gas control power switch to the “OFF” po- sition. -
Page 47: Inner Door Gasket Replacement
Step 6. Remove the connectors attached to the re- settable thermal switch on the manifold mount. 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. Step 8. -
Page 48: Inner Door Installation
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. Set the flange section first, and this will help to achieve the proper overlap position. -
Page 49: Screenlok ® Flame Arrestor Cleaning
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. -
Page 50: Common Terms
Common Terms Common Terms British Thermal Units Energy Cut Off Gallons per Minute Hertz Kilowatts per hour Light Emitting Diode National Pipe Thread Ohms Ohms of resistance Pounds per Square Inch Revolutions per Minute Volts Alternating Current W.C. Inches of Water Column °C Degrees Centigrade °F... -
Page 51: Parts List
1. Blower Complete 2. Air Mixing Inlet 3. Pressure Switch 4. Blower Temperature Switch 5. Blower Gasket 6. Blower Power Cord 7. Vent Adapter w/ Vent Term. 8. Condensate Hose Kit 9. Heat Trap Outlet 10. Hot Water Outlet Anode 11. - Page 52 Email parts@bradfordwhite.com techserv@bradfordwhite.com www.bradfordwhite.com...
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