115 Vac Circuit Trace - Bradford White M1TW40S Series Service Manual

115 VAC Circuit Trace

Step 1. Verify 115VAC and proper polarity at wall outlet.
Step 2. With unit plugged in and control power switch in the "ON" position verify LED status.
LED status
None, Control LED not
on or flashing.
Disconnect cord set as
shown in photo 28
Using a volt meter set
to volts AC, is there
115VAC across
terminals shown in
photo 29 ?
Y
Is there 115VAC
across terminals
shown in photo 30 ?
N
Incorrect supply
voltage polarity
Locate black & white wires at
connector, It may be necessary to pull
back wire sheath to identify wire colors.
(see photo 32)
Is there 115VAC
across black & white
wires as shown in
photo 32?
N
Call for technical
support.
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30
LED status
Short flash, once every
four seconds.
Waiting for
call for heat.
N
Y
Reconnect cord set
shown in photo 28.
Disconnect wire harness
from gas control
(see photo 31).
Replace gas
Y
control.
TTW SERVICE PROCEDURE IX
115 volt potential exposure. Use caution
making voltage checks to avoid personal injury.
LED status
"Heartbeat", alternates
bright/dim.
Thermostat calling
for heat
28
Check for damage to
AC supply power cord.
N
Replace Blower
32
Wire sheath pulled back to
Check for 115VAC between black & white wires.
-NOTE-
Electronic meter probes required. Use care not to
damage connector during this check.
115 VAC Trace
WARNING
LED status
Various flashing error
codes.
Verify error code as
listed on page 13
29
Y
Repair damage
Wire harness
identify wire colors
30
31
Page 30