Heater Will Not Fire - C
Start
Go to “INITIAL
TROUBLESHOOTING”
Continue to observe heater for
several minutes. Cycle heater
on and off several times.
Observe for delayed or rough
ignition, poor combustion,
premature extinction of flame,
evidence of boiling, or
operation of any diagnostic
LED. Go to pertinent
troubleshooting section if any
malfunction is observed.
Replace Control Board.
Replace Gas Valve with
identical part.
Fix wiring between TH and
GND terminals of Ignition
Control Module and Control
Board.
Replace Control Board.
Fix wiring between GAS
terminals on Control Board
and Gas Valve.
NOTE 1 :
Voltage appears
immediately after call for heat,
and may be on for only about
30 seconds.
NOTE 2 :
Voltage appears about
24 seconds after call for heat,
and may be on for only about
7 seconds.
Verify that gas supply is open
all the way to Gas Valve, and
Gas Valve is set at “on”
position.
Check for 24 VAC to Gas
Valve terminals during ignition
try. (Voltage appears about 24
seconds after call for heat).
SEE NOTE 2.
Turn off power to
heater for 5 seconds,
and turn back on.
Make sure temperature
setting is above
water temperature.
Wait one minute.
Does heater fire and
stay on?
Did Blower come on?
Verify that gas is flowing
to burner during ignition
try. Observe gas meter
for movement during
ignition try (wait for
about 30 seconds after
calling for heat).
Check for 24 VAC
between TH and GND
terminals on Ignition
Control Module.
SEE NOTE 1.
Check for 24 VAC
between TH and GND
terminals on Control
Board. SEE NOTE 1.
Check for 24 VAC
between GAS
terminals on Control
Board. SEE NOTE 2.
Replace Control
Board.
NO
CONTINUE
YES
YE
S
YES
NO
NO
YES
NO
YES
NO
NO
YES
YES
NO
YES
YES
Is “SERVICE HEATER” LED
“on”?
Go to “BURNER
TROUBLESHOOTING”
(Page 47)
Go to “HEATER WILL NOT
FIRE-D” (Page 44)
Check for 24 VAC between
VAL and GND terminals on
Ignition Control Module.
SEE NOTE 2.
Check for 24 VAC between
VAL and GND terminals on
Control Board. SEE NOTE 2.
If any red diagnostic LED’s
(AGS, AFS, SFS, HLS, PS, or
THERMISTOR) come “on”, go
to to Pages 45 and 46.
Did burner fire at all?
Replace Ignition Control
Module.
NO
YES
Fix wiring between VAL and
GND terminals of Ignition
Control Module and Control
Board.
NO
YES
NO
NO
