Bradford-White Corp U4TW60TFRN, U4TW50TFRN, U4TW40T*FRN Control Timings, Wiring Diagram

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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 Load Lockout	Indefinite (cycle power to reset)

Hardware Error Lockout	Indefinite (self clears if fault clears for at least 15 seconds)

Wiring Diagram

BLOWER
BLOWER			BLOWER
TEMPERATURE			MOTOR
SWITCH
			M
PRESSURE	G
PRESSURE			BL
SWITCH W		Y	BL
SWITCH W		Y
	W		R
BK		Y
G		Y
G
PILOT

W

Honeywell

	PLUG
	BKBK
	BK
G W	Y
G W
R
BK BL	WATER TEMPERATURE

	SENSOR
RESETTABLE	FLAMMABLE
RESETTABLE
THERMAL	VAPOR SENSOR
THERMAL

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Contents Service Manual Table of Contents Page Page Introduction Bradford White ECO-DEFENDER Safety SystemHow the Safety System Works How to Use this ManualTools Required Tools Required for ServiceSpecifications Gallon Vent TablesSpecifications Control Timings Wiring DiagramNormal Heating Sequence Power Up SequenceSequence of Operation Abnormal Operation Normal Heating Sequence cont’dAbnormal Operation cont’d Sequence of Operation Sequence of Operation LED Status Control Status Probable Cause Service Procedure TroubleshootingTroubleshooting Troubleshooting Burner Inspection Burner MaintenanceBurner Cleaning Procedure Burner Cleaning Procedure cont’d Pilot Inspection, Testing and Replacement Pilot MaintenancePilot 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 Removal Blower ReplacementBlower Installation Blower Temperature Switch Testing Blower Temperature Switch TestingBlower Installation cont’d Switch Setting Blower Temperature Switch Testing cont’dBlower Temperature Switch Replacement Blower Temperature Switch ReplacementThermal Well Testing Thermal Well TestingDetermine Water Temperature Inside Tank Determine Tank TemperatureThermal Well Testing cont’d Gas Control & Thermal Well Removal From Water Heater Component DisassemblySensor Resistance at Various Temperatures Gas Control Removal Gas Control Removal From Thermal Well cont’d Gas Control AssemblyGas Control Assembly to the Thermal Well 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 TraceBlower Removal Remove the Blower to Gain Access to the Flue BaffleDip Tube Inspection Remove the Blower to Gain Access to the Flue Baffle cont’dDip Tube Inspection and Replacement Anode Inspection Anode Inspection and ReplacementInner Door Removal Inner Door Removal ProcedureInner Door Gasket Replacement Procedure Inner Door Gasket ReplacementInner Door Removal Procedure cont’d Inner Door Installation with Gasket Inner Door InstallationScreenLok Flame Arrestor Cleaning Procedure Arrestor CleaningCommon Terms Common TermsPart Name and Description Parts ListParts@bradfordwhite.com Techserv@bradfordwhite.com