Bradford White TW4-75S-76B-3X - Manual (Page 30)

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