Page 13
Note: The Troubleshooting section replaces pages 4-6 in the Defender Atmospheric service manual, p/n 238-44943-00.
LED Status Control Sta tus Probable C ause Service Procedure
None (LED
not on or
flashin
g)
Electrica l powe r not
present
Controlpower switch in "OFF"
position.
Su
pp
l
y
volta
g
e interru
p
ted.
Turn Power On
One short
flash every
four seconds
Stand-by mode,
Thermostat is
satis fied
(
no faults
)
Temperature demandis satisfied
(no call for h eat) Normal operation
Alternates
bright and
dim
(
heartbeat
)
Thermost at calling
for heat (no fault)
Tank tempe rature be low
setpoint of thermostat Normal operation
Short flash
once every
second
Weak pilot signal
on las t call for h eat
1. Unstable pilot
2. Pilot t ube blo cked o r restricte d
3. Oxidat ion build -up on p ilot
electrode
4. Wire d amage to pilot
assembly or bad connection at
gas control
1. See Burner Inspectionon
page 17
2-4. See Pilot Inspection,
Testing and Replacement on
page 19
Two flashes,
three second
pause
Relay no t wor king Faulty re lay
1. Verify cord sets a re fully
plugged in
2. See Relay Replacement on
p
a
g
e 28
Three
flashes,
three second
pause
Relay no t wor king Faulty re lay
1. Verify cord sets a re fully
plugged in
2. See Relay Replacement on
page 28
Four flas hes,
three second
pause
Excessive tank
temperature,
system mustbe
reset
1. Thermal w ell se nsor o ut of
calibrat ion
2. Faulty gas control
1. Test Gas Control& Thermal
Well
2. Replace gascontrol if
necessar
y
Five flas hes,
three second
pause
False pilot flame
present Pilot valve stuck in open position Replace gas control
Six flashe s,
one flash,
three second
pause (Soft
Lockout)
Failed t o light p ilot,
system resets after
(5) minute s
1. Unstable pilot
2. Pilot tube block orrestricted
3. Oxidat ion build -up on p ilot
electrode
4. Wire d amage to pilot
assembly or bad connection at
g
as valve
1. See Burner Inspectionon
page 17
2-4. See Pilot Inspection,
Testing and Replacement on
page 19

Observe the green LED on the water heater gas

control. Diagnostic codes are displayed with a 3

second pause before repeating. Once the diagnostic

code is known, check and repair the water heater, as

recommended in the table below.

Troubleshooting
Green LED
13