Bradford-White Corp U4TW60TFRN, U4TW50TFRN, U4TW40TFRN service manual* VAC Circuit Trace

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115 VAC Circuit Trace

WARNING

115 volt potential exposure. Use caution making voltage checks to avoid

personal injury.

LED status:

None, control LED not on or flashing.

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?

Y

Is there 115VAC across terminals shown in photo 11?

N

Incorrect supply voltage polarity.

LED status:	LED status:
Short flash	“Heartbeat”,
once every four	alternates
seconds.	bright/dim.

Waiting for call	Thermostat call-
for heat.	ing for heat.
9	10

N

		Check for damage	Y
		Check for damage
		to AC supply
N		to AC supply
N		power cord.
Reconnect cord set
shown in photo 9.		N

Replace blower. Disconnect wire har-

ness from gas control

(see photo 12).

Wire harness

LED status:

Various flash-

ing error codes.

Verify error

code as listed

on page 17.

11

Repair damage.

12

Locate black & white wires at connector, it may be necessary to pull back wire sheath to identify wire colors (see photo 13).

	Is there 115VAC across	Y
	Is there 115VAC across	Replace gas control.
	black & white wire as	Replace gas control.
	black & white wire as
	shown in photo 13?
	N
	Call for technical support.

13

Wire sheath pulled back to

identify wire colors

Check for 115VAC between black and white wires.

-NOTE-

Electronic meter probes required. Use car not to

damage connector during this check.

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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