Bradford White U-TW4-75S-76R-3N - Manual (Page 17)

Page 17
LED Status Control Status Probable Cause Service Procedure
None (LED
not on or
flashing)
No electrical pow er
Control pow er sw itch in "OFF"
position.
Supply voltage interrupted.
Turn Pow er On
One short
flash every
four seconds
Stand-by mode,
Thermostat is
satisfied (no faults)
Temperature demand is satisfied
(no call for heat)
Normal operation
Alternates
bright and
dim
(heartbeat)
Thermostat calling
for heat (no fault)
Tank temperature below
setpoint of thermostat
Normal operation
Short flash
once every
second
Weak pilot signal
on last call for heat
1. Unstable pilot
2. Pilot tube blocked or restricted
3. Oxidation build-up on pilot
electrode
4. Wire damage to pilot
assembly or bad connection at
gas control
1. See Burner Inspection on
page 20
2-4. See Pilot Inspection,
Testing and Replacement on
page 22
Tw o flashes,
three second
pause
Pressure sw itch not
w orking-closed
position
1. Pressure sw itch tubing kinked
or blocked
2. Blocked pressure tap on
sw itch or blow er
3. Faulty pressure switch
1-3. See Pressure Sw itch
Testing on page 25
Three
flashes,
three second
pause
Pressure sw itch or
blow er temperature
sw itch not w orking-
open position
1. Vent blockage or improper
vent configuration
2. Pressure sw itch tubing kinked
or blocked
3. Faulty pressure sw itch
4. Blow er not spinning up to
speed
5. Blow er temperature or
exhaust temperature too high
6. Faulty blow er temperature
sw itch
1. Check vent or vent tables
2-3. See Pressure Sw itch
Testing on page 25
4. See Blow er Testing on
page 28
5-6. See blow er Temperature
Sw itch Testing on page 31
Four flashes,
three second
pause
Excessive tank
temperature,
system must be
reset
1. Thermal w ell sensor out of
calibration
2. Faulty gas control
1. Test Gas Control & Thermal
Well
2. Replace gas control if
necessary
Five flashes,
three second
pause
False pilot flame
present
Pilot valve stuck in open position Replace gas control
Observe the green LED on the water heater gas con-
trol. Error codes are displayed with a 3 second pause
before repeating. Once the error code is known, check
and repair the water heater, as recommended in the
table below.
Troubleshooting
Green LED
17