Bradford-White Corp U4TW50T*FRN, U4TW40T*FRN, U4TW60T*FRN service manual Troubleshooting

Page 18

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 vent or vent

 

 

 

 

2.

Pressure switch tubing kinked

tables

 

 

 

Pressure switch or

or blocked

2-3. See Pressure Switch

 

 

Six flashes,

blower temperature

3.

Faulty pressure switch

Testing on page 25

 

 

two flashes,

switch opened

4.

Vent termination being

4. Refer to venting section

 

 

three second

during burner

affected by wind

of installation manual

 

 

pause (Soft

operation. System

5.

Blower not spinning up to

5. See Blower Testing on

 

 

Lockout)

resets after (5)

speed

page 28

 

 

 

minutes

6.

Blower temperature or

6-7. See Blower

 

 

 

 

exhaust temperature too high

Temperature Switch

 

 

 

 

7.

Faulty blower temperature

Testing on page 31

 

 

 

 

switch

 

 

 

 

 

1.

Unstable pilot

 

 

 

Six flashes,

 

2.

Pilot tube block or restricted

1. See Burner Inspection

 

 

 

3.

Oxidation build-up on pilot

on page 20

 

 

three

Pilot flame

 

 

electrode

2-4. See Pilot Inspection,

 

 

flashes,

extinguished,

 

 

4.

Wire damage to pilot

Testing and Replacement

 

 

three second

system auto resets

 

 

pause (Soft

after (5) minutes

assembly or bad connection at

on page 22

 

 

gas control

5. Refer to Installation &

 

 

Lockout)

 

 

 

 

5.

Insufficient combustion air

Operation Manual

 

 

 

 

 

 

 

 

6.

Insufficient gas pressure

 

 

 

Six flashes,

Undesired false

 

 

 

 

 

four flashes,

 

 

 

 

 

pilot flame sensed,

Pilot valve stuck in open position

Replace gas control

 

 

three second

 

 

pause

system auto resets

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

1.

Flammable vapor present

 

 

 

 

Flammable vapor

2.

Flammable vapor sensor

 

 

 

Seven

sensor or

exposed to excessive moisture

 

 

 

flashes,

resettable thermal

3.

Flammable vapor sensor

See Flammable Vapor

 

 

three second

switch fault

exposed to extreme ambient

Sensor Testing on page 40

 

 

pause

detected, see

temperature

 

 

 

 

warning label

4.

Resettable thermal switch

 

 

 

 

 

open

 

 

 

 

 

1.

Flammable vapor sensor out

 

 

 

Eight

Flammable vapor

of specification; verify Flammable

 

 

 

flashes, one

Vapor Sensor (FVS) resistance is

 

 

 

sensor out of

See Flammable Vapor

 

 

flash, three

specification,

not below 25 kŸ.

Sensor Testing on page 40

 

 

second

2.

Possible short in flammable

 

 

possible short

 

 

 

pause

vapor sensor or resettable

 

 

 

 

 

 

 

 

 

thermal switch wiring

 

 

 

 

 

 

 

 

 

Page 18

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Contents Service Manual Table of Contents Page Page Bradford White ECO-DEFENDER Safety System IntroductionHow to Use this Manual How the Safety System WorksTools Required for Service Tools RequiredSpecifications Vent Tables GallonSpecifications Wiring Diagram Control TimingsPower Up Sequence Sequence of OperationNormal Heating Sequence Normal Heating Sequence cont’d Abnormal OperationAbnormal Operation cont’d Sequence of Operation Sequence of Operation Troubleshooting LED Status Control Status Probable Cause Service ProcedureTroubleshooting Troubleshooting Burner Maintenance Burner Cleaning ProcedureBurner Inspection Burner Cleaning Procedure cont’d Pilot Maintenance Pilot Inspection, Testing and ReplacementPilot Inspection, Testing and Replacement cont’d Page Pressure Switch Testing Pressure Switch TestingPressure Switch Testing cont’d Pressure Switch Replacement Pressure Switch ReplacementBlower Testing Blower TestingPage Blower Replacement Blower InstallationBlower Removal Blower Temperature Switch Testing Blower Installation cont’dBlower Temperature Switch Testing Blower Temperature Switch Testing cont’d Switch SettingBlower Temperature Switch Replacement Blower Temperature Switch ReplacementThermal Well Testing Thermal Well TestingDetermine Tank Temperature Thermal Well Testing cont’dDetermine Water Temperature Inside Tank Component Disassembly Sensor Resistance at Various TemperaturesGas Control & Thermal Well Removal From Water Heater Gas Control Removal Gas Control Assembly Gas Control Assembly to the Thermal WellGas Control Removal From Thermal Well cont’d Gas Control Assembly to the Thermal Well cont’d Flammable Vapor Sensor Testing Flammable Vapor Sensor TestingVAC Circuit Trace Safety Circuit Voltage Trace Safety Circuit Voltage TraceRemove the Blower to Gain Access to the Flue Baffle Blower RemovalRemove the Blower to Gain Access to the Flue Baffle cont’d Dip Tube Inspection and ReplacementDip Tube Inspection Anode Inspection and Replacement Anode InspectionInner Door Removal Procedure Inner Door RemovalInner Door Gasket Replacement Inner Door Removal Procedure cont’dInner Door Gasket Replacement Procedure Inner Door Installation Inner Door Installation with GasketArrestor Cleaning ScreenLok Flame Arrestor Cleaning ProcedureCommon Terms Common TermsParts List Part Name and DescriptionParts@bradfordwhite.com Techserv@bradfordwhite.com