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

 

 

 

 

 

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

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.

Page 41

41

Page 41
Image 41
Bradford-White Corp U4TW60T*FRN, U4TW50T*FRN, U4TW40T*FRN service manual VAC Circuit Trace