Troubleshooting - Bradford White TTW 75 SERIES Service Manual

Observe green LED indicator on
Electronic gas control. Error flash codes
are displayed with a three second pause
before repeating. Check and repair the
system as noted in the troubleshooting
table below.
LED Status
None, control LED not
on or flashing
Short flash, once every
four seconds
"Heartbeat", alternates
bright/dim
Short flash once per
second
Two flash, three
second pause
Three flash, three
second pause
Four flash, three
second pause
Five flash, three
second pause
12
Control
Status
No electrical Control power switch in "OFF" position.
power Supply voltage interrupted.
Stand-by mode,
Waiting for call for Temperature demand is satisfied
heat (no fault).
Thermostat calling
Tank temperature below set point of thermostat.
for heat (no fault).
1. Unstable pilot.
Weak pilot signal 2. Pilot tube block or restricted.
on last call for 3. Oxidation build up on pilot electrode.
heat. 4. Wire damage to pilot assembly or bad
connection at gas valve.
Pressure switch 1. Pressure switch tubing kinked or blocked.
not working- 2. Blocked pressure tap on switch or blower.
closed position. 3. Faulty pressure switch.
1. Vent blockage or improper vent configuration.
Pressure switch 2. Pressure switch tubing kinked or blocked.
or blower temp. 3. Faulty pressure switch.
switch not working 4. Blower not spinning up to speed.
-open position. 5. Blower temp or exhaust temp too high
6. Faulty blower temperature switch.
Excessive tank
1. Thermal well sensor out of calibration.
temperature.
2. Faulty gas control.
System must be
3. Pluming leak
reset.
Undesired-false
pilot flame 1. Pilot valve stuck in open position.
present.
Probable Cause

Troubleshooting

Green LED
Indicator
Service
Procedure
Turn power on
Normal operation.
Adjust thermostat to
temp level
Normal operation.
Adjust thermostat to
temp level
1. Page 14
2-4. Page 16
Page 17
1. Check vent or vent tables.
2 & 3 Page 18
4. Page 19
5 & 6 Page 21
1. Page 23
2. Replace gas control,
page 23
Replace gas control,
page 23
Page 12