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DIAGNOSTICS FOR HONEYWELL CONTROL
LED Status Control Status Probable Cause
None (LED not on or
flashing)
Millivolt power is not
present. Light pilot.
1. Gas valve is functioning
normally
2. Gas valve is not powered.
Light pilot
One flash and three
second pause.
If set point knob is in
"PILOT" position then pilot
flame is detected.
(no
faults).
Gas valve is powered and waiting
for the set point knob to be turned
to a water temperature setting. If
the set point knob is at desired
setting the thermostat is satisfied.
LED strobe (two quick
flashes) and three second
pause
Thermostat calling for heat
(no faults)
Water heater operating normally.
LED on continuously.
Set point knob has been
recently turned to the
"OFF" position.
Set point knob was recently turned
to "OFF" position. Wait until LED
goes out before attempting to
relight
Two flashes and three
second pause.
Weak pilot flame detected.
System will reset when
pilot flame is sufficient.
1. Unstable pilot.
2. Pilot tube blocked or
restricted.
Three flashes and three
second pause.
Insufficient water heating.
System will reset.
1. Temperature sensor out of
calibration.
2. Possible short.
Four flashes and three
second pause.
Excessive tank
temperature. System must
be reset.
1. Temperature sensor out of
calibration.
2. Faulty gas valve.
Five flashes and three
second pause.
Temperature sensor fault.
1. Damage to the temperature
wire.
2. Temperature sensor
resistance out of range.
3. Replace temperature sensor.
4. If temperature sensor
replacement does not correct
the problem; Verify control is
not wet or physically damaged
5. Turn set point knob to "OFF"
position. Turn set point knob
to "PILOT" position and light
pilot.
6. Replace gas valve if five flash
error persists.