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®
TTW Series
Through-The-Wall Gas Water Heaters
SERVICE
MANUAL
Troubleshooting Guide
and Instructions for Service
(To be performed ONLY by
qualified service providers)
Models Covered
by This Manual:
M1TW40S*F (BN,CX,SX)
M1TW50S*F (BN,CX,SX)
M1TW60T*F (BN,CX,SX)
M4TW40T*F (BN,SX)
M4TW50T*F (BN,SX)
M4TW60T*F (BN,SX)
M2TW50T*F (BN,CX,SX)
M2TW65T*F (BN,CX,SX)
TW450S65F (B,C,S)*(N,X)
TW465S65F (B,C,S)*(N,X)
(*) Denotes Warranty Years
Manual 238-46238A-00A Save this manual for future reference
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The Bradford White Through-The-Wall Gas Water Heaters Page TTW Service Procedure Introduction 4 - - - How to use this manual 5 - - - Tool required for service 5 - - - Specifications 6 - - - Control Timings 9 - - - Sequence of Operation 10 - - - Troubleshooting 13 - - - Burner Inspection, Cleaning and Replacement 15 I Pilot Testing, Cleaning and Replacement 17 II Pressure Switch Testing and Replacement 18 III Blower Testing and Rep
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CAUTION WARNING: If the information in these instructions Incorrect operation of this appliance is not followed exactly, a fire or explosion may may create a hazard to life and result causing property damage, personal injury, or property and will nullify the warranty. death. FOR YOUR SAFETY DANGER Do not store or use gasoline or other Do not store or use gasoline or other flammable, flammable, combustible, or corrosive combustible, or corrosive vapors and liquids in the vapors and liqui
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Introduction The new Bradford White TTW1, TTW2 & TW4 water heaters are designed to provide reliable performance with enhanced standard features. New design features include reliable spark to pilot ignition system, enhanced diagnostics, simplified servicing, significantly quiet operation and additional vent lengths. Spark to Pilot Ignition System - employing the spark to pilot ignition system promotes reliable and consistent pilot and main burner ignitions to provide hot water on demand. Int
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How to Use This Manual It is intended for this manual to be used by qualified service personal for the primary purpose of troubleshooting and repair of the Bradford White TTW Series water heaters. Understanding the sequence of operation section of this manual will contribute greatly to troubleshooting the water heater. The Honeywell WV4460E Electronic Gas Control will display error codes in the event of abnormal operation. Error codes are listed in the troubleshooting chart beginning on page
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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 or Propane. Unit must match gas type supplied. Gas Pressure 5.0" W.C. min. for Nat gas, 11.0" W.C. min. for L.P. gas, 14.0" W.C. maximum (Nat. & L.P.) Venting System Power vent through the wall or vertical through the roof Approved Vent Materials PVC, CPVC or ABS Minimum Clearance 18" from top, 24" from front, 4" sides and rear. for Servic
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Specifications Vent Tables Venting Specifications for: 40 Gallon 50 Gallon 60 Gallon 2" Diameter (5.1 cm) PVC Vent Connector Lengths # of Maximum Straight Minimum Straight Terminating Elbows Length ft (m) Length ft (m) Through the Wall 1 45 (13.7) 2 (.6) Through the Wall 2 40 (12.2) 2 (.6) Through the Wall 3 35 (10.7) 2 (.6) Through the Wall 4 30 (9.2) 2 (.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 (2.1) Through the Roof 3 35 (10.7
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Specifications Vent Tables Venting Specifications for: 48 Gallon 65 Gallon 3" Diameter (7.6 cm) PVC Vent Connector Lengths # of Maximum Straight Minimum Straight Terminating Elbows Length ft (m) Length ft (m) Through the Wall 1 55 (16.8) 2 (.6) Through the Wall 2 50 (15.2) 2 (.6) Through the Wall 3 45 (13.7) 2 (.6) Through the Wall 4 40 (12.2) 2 (.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 (2.1) Through the Roof 3 45 (13.7) 7 (2.1)
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Specifications Control Timings Ignition State Timing Pre-purge 2 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 24 to reset) Verify Resistive Delay Retry after 2 Minutes (repeats 5 times) Simulated Resistive Load Lock
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Sequence of Operation 1 Start Up. Upon power up, the control runs a safe-start check with a typical start-up delay of 5 seconds. 2 Flammable Vapor. To assure no outputs are energized if the “Flammable Vapor Sensor” is out of range, the control will test the “Flammable Vapor Sensor” for proper operating range. If the “Flammable Vapor Sensor” is within range the control resumes normal operation with no perceptible delay. If the “Flammable Vapor Sensor” is out of range, the control LED immediately
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Sequence of Operation Steady state operation. 7 During Steady State Operation the Control Monitors: Thermostat temperature sensor- When set point temperature is satisfied, gas valve is shut down and blower will post purge for 15 seconds. Control LED flashes a short flash once every 4 seconds (idle) status code. Pressure switch / Blower temperature switch- If either switch opens, pilot valve and main valve is shut down. The blower continues to runs for 30 seconds attempting to close the circuit.
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Sequence of Operation 3. Pressure Switch/Blower Temperature Fault: a) Pressure switch closed at start of call for heat - The gas control waits four seconds then, proceeds to flash 2 times with 3 second pause. The control waits 2 minutes and then turns on blower for 30 seconds. The blower turns off after 30 seconds and the control waits for pressure switch to open. Any time the Pressure switch opens, the blower turns on (or stays on) and the control proceeds to waiting for pressure switch to clos
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Troubleshooting Green LED Indicator Observe green LED indicator on Electronic gas control. Error flash codes are displayed with a three second pause before repeating. Check and repair the system as noted in the troubleshooting table below. Control Service LED Status Probable Cause Status Procedure None, control LED not No electrical Control power switch in “OFF” position. Turn power on on or flashing power Supply voltage interrupted. Stand-by mode, Normal operation. Short flash, once every
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Troubleshooting Control Service LED Status Probable Cause Status Procedure 1. Unstable pilot. Failed to light 1. Page 15 2. Pilot tube blocked or restricted. Six-one flash, three pilot. 3. Oxidation build up on pilot electrode. second pause System auto 2-4. Page 17 4. Wire damage to pilot assembly or bad resets. connection at gas valve. 1. Check vent or vent tables. Pressure switch 1. Vent blockage or improper vent configuration. 2 & 3 Page 18 or blower temp 2. Pressure switch tubing kinked
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TTW SERVICE PROCEDURE I Burner Operation Inspection, Adjustment, Cleaning and Replacement Burner Inspection and Air Shutter Adjustment. 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. Pilot flame should be stable, some causes for an unstable pilot flame are: a) Water heater vent is less than the allowable vent length. b) Gas pressure is out of specification. c) Pilot flame not
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TTW SERVICE PROCEDURE I Burner Operation Inspection, Adjustment, Cleaning and Replacement Burner Cleaning Burner Cleaning Remove Outer door. Step 1. Step 1. Position gas control power switch to the Position gas control power switch to the “OFF” position and unplug heater from wall “OFF” position and unplug heater from wall outlet. outlet. Step 2. Turn off gas supply to water heater. Step 2. Turn off gas supply to water heater. Slide inner door open from left to right. Step 3. Remove outer jack
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TTW SERVICE PROCEDURE II Pilot testing, Cleaning and Replacement Pilot Inspection, Testing and Replacement Pilot Inspection, Testing and Replacement Step 1. Position gas control power switch to the Step 1. Position gas control power switch to the “OFF” position and unplug heater from wall “OFF” position and unplug heater from wall outlet. outlet. Remove Outer door. Step 2. Step 2. Turn off gas supply to water heater. Turn off gas supply to water heater. Slide inner door open from left to right
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TTW SERVICE PROCEDURE III Pressure Switch Testing and Replacement WARNING Pressure Switch Testing 115 volt potential exposure. Use caution Step 1. Position power switch on gas control making voltage checks to avoid personal injury. to the “OFF” position. Step 2. Remove the three screws (Phillips screw driver) from control access cover on blower assembly and remove cover (see photo 1). Step 3. Carefully remove pressure switch from blower housing (see photo 2) 1 2 With steps 1,2 & 3 Pressure Sw
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TTW SERVICE PROCEDURE III Pressure Switch Testing and Replacement WARNING Pressure Switch Replacement 115 volt potential exposure. Use caution to avoid personal injury. Step 1. Position gas control power switch to “OFF” position. Step 2. Remove the three screws (Phillips screw driver) from control access cover on blower assembly and remove cover (see photo 3). Pressure Switch 3 4 Step 3. Carefully remove pressure switch from blower housing (see photo 4) Slide pressure switch in direction o
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TTW SERVICE PROCEDURE IV Blower Testing and Replacement WARNING Blower Testing 115 volt potential exposure. Use caution when making voltage checks to avoid personal injury. Step 1. Position gas control power switch to “ON” position and adjust control to call for heat. 7 Step 2. Remove the three screws (Phillips Screw driver) from control access cover on blower assembly and remove cover (see photo 7). Remove exhaust adapter Connect Disconnect vent Disconnect manometer to system from top of Do
