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®
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
U2TW50T*FRN
U2TW65T*FRN
UTW450S60FR*N
UTW465S60FR*N
(*) Denotes Warranty Years
Manual 238-48385-00A Save this manual for future reference
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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 _____
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WARNING If the information in these instructions is not followed exactly, a fire or ex- plosion may result causing property damage, personal injury, or death. What to do if you smell gas: Do not try to light any appliance Do not touch any electrical switch; do not use any phone in your build- ing Immediately call your gas supplier from a neighbor’s phone. Follow the gas supplier’s instructions. If you cannot reach your gas supplier, call the fire department. Installation and service must
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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 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. Hydrogen gas can be
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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. A number of exclusive design features are incorporated in the system that will require additional knowledge on the part of the qualified
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How to Use this Manual 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 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. Please read the service manual completely before attempti
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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. The meter you select must have the capability to measure volts
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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 18” from top, 24” from front, 4” sides and rear. Servicing 150 PSI maximum allowable working pressure. Check local codes for Water Supply
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Specifications 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 Maximum Straight Minimum Straight Terminating # of Elbows Length ft (m) 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) Th
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Specifications Vent Tables Venting Specifications for: 48 Gallon—60,000 BTU/hr. 65 Gallon—60,000 BTU/hr. 3” Diameter (7.6 cm) PVC Vent Connector Lengths Maximum Straight Minimum Straight Terminating # of Elbows Length ft (m) 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
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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 1.5 seconds (2 second maximum, 1 second minimum) Post-purge 15 seconds PS Fault Delay (failed open/close) Retry after 2 minutes Soft Lockout Retry after 5 minutes TCO Limit Lockout Indefinite (see page 34 to reset) Verify Resistive Delay Retry after 2 minutes (repeats 5 times) Simulated Resistive
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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. 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 s
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Sequence of 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. 8. Steady State Operation: During steady state operation, the gas control monitors: Thermostat Temperature Sensor: When the setpoint temperature is sat- isfied, the gas control is shutdown, and th
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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. 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. The
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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. This cycle repeats as
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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 sec- ond pause. The gas control waits 5 minutes before repeat
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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 Green LED and repair the water heater, as recommended in the table below. LED Status Control Status Probable Cause Service Procedure None (LED Control power switch in "OFF" not on or No electrical power position. Turn Power On flashing) Supply voltage interrupted. One short Stand-by mode, Temperature demand is satisfi
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Troubleshooting LED Status Control Status Probable Cause Service Procedure 1. Unstable pilot Six flashes, 2. Pilot tube block or restricted 1. See Burner Inspection one flash, Failed to light pilot, 3. Oxidation build-up on pilot on page 20 three second system resets after electrode 2-4. See Pilot Inspection, pause (Soft (5) minutes 4. Wire damage to pilot Testing and Replacement Lockout) assembly or bad connection at on page 22 gas valve 1. Vent blockage or improper vent configuration 1. Check
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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, damaged or un- 3. Replace thermal well three flashes, See Thermal Well Testing on plugged or gas con- 4. Verify control is not wet or three second page 34 trol electronics fault physically damaged pause detected 5. Reset control on/off switch 6. Replace gas control if 8-3 error persists 1. Verify co
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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 unsta- ble 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. A
