Bradford White U-TW4-75S-76R-3N - Manual (Page 18)

Page 18
LED Status Control Status Probable Cause Service Procedure
Six flashes,
one flash,
three second
pause (Soft
Lockout)
Failed to light pilot,
system resets after
(5) minutes
1. Unstable pilot
2. Pilot tube block or restricted
3. Oxidation build-up on pilot
electrode
4. Wire damage to pilot
assembly or bad connection at
gas valve
1. See Burner Inspection
on page 20
2-4. See Pilot Inspection,
Testing and Replacement
on page 22
Six flashes,
tw o flashes,
three second
pause (Soft
Lockout)
Pressure sw itch or
blow er temperature
sw itch opened
during burner
operation. System
resets after (5)
minutes
1. Vent blockage or improper
vent configuration
2. Pressure sw itch tubing kinked
or blocked
3. Faulty pressure sw itch
4. Vent termination being
affected by w ind
5. Blow er not spinning up to
speed
6. Blow er temperature or
exhaust temperature too high
7. Faulty blow er temperature
sw itch
1. Check vent or vent
tables
2-3. See Pressure Sw itch
Testing on page 25
4. Refer to venting section
of installation manual
5. See Blow er Testing on
page 28
6-7. See Blow er
Temperature Sw itch
Testing on page 31
Six flashes,
three
flashes,
three second
pause (Soft
Lockout)
Pilot flame
extinguished,
system auto resets
after (5) minutes
1. Unstable pilot
2. Pilot tube block or restricted
3. Oxidation build-up on pilot
electrode
4. Wire damage to pilot
assembly or bad connection at
gas control
5. Insufficient combustion air
6. Insufficient gas pressure
1. See Burner Inspection
on page 20
2-4. See Pilot Inspection,
Testing and Replacement
on page 22
5. Refer to Installation &
Operation Manual
Six flashes,
four flashes,
three second
pause
Undesired false
pilot flame sensed,
system auto resets
Pilot valve stuck in open position Replace gas control
Seven
flashes,
three second
pause
Flammable vapor
sensor or
resettable thermal
sw itch fault
detected, see
w arning label
1. Flammable vapor present
2. Flammable vapor sensor
exposed to excessive moisture
3. Flammable vapor sensor
exposed to extreme ambient
temperature
4. Resettable thermal sw itch
open
See Flammable Vapor
Sensor Testing on page 40
Eight
flashes, one
flash, three
second
pause
Flammable vapor
sensor out of
specification,
possible short
1. Flammable vapor sensor out
of specification; verify Flammable
Vapor Sensor (FVS) resistance is
not below 25 kŸ.
2. Possible short in flammable
vapor sensor or resettable
thermal sw itch w iring
See Flammable Vapor
Sensor Testing on page 40
Troubleshooting
18