9
After ignitor is
warmed up, does gas valve
open?
YES
NO
Test for 24V at valve
during valve opening
period (usually 30-45
seconds after power to the
heater). Is there 24V to
valve for 8 seconds?
NO
Possibly, the circuit board
and/or wiring harness is
faulty. These should be
replaced.
Check to make sure gas pressure is within
minimum and maximum inputs, as indicated
on AGA burner rating label. Is gas pressure
OK?
YES
Correct
problem.
NO
Replace gas
valve.
YES
YES
Does the burner light?
NO
Is the gas cock in the
ON position?
YES
Correct
problem.
NO
Make sure gas lines were purged
of air.
YES
YES
Does the burner stay
on?
NO
Does the burner stay on for
approx. 8 seconds and then shut
off?
YES
Is the heater properly grounded?
Is the heater’s polarity correct?
YES
With microammeter, check DC
voltage at flame rod. Is it greater
than 0.7 microamps?
YES
Check to make sure
flame sensor wire is OK
and then replace circuit
board.
NO
Sensing rod is faulty or flame is weak.
Check to make sure heater is
operating at proper gas pressure as
indicated on AGA burner rating label
and then replace sensing rod if
needed.
NO
Correct problem.
NO
Does the burner come
on and then turn off
immediately (1 or 2
seconds).
YES
Check to make sure that the gas pressure is
within minimum and maximum inputs as
indicated on the AGA burner rating label. Is
gas pressure OK?
Correct
problem.
NO
Exhaust pressure
switch may be faulty
or there is a restriction
in the exhaust.
YES
YES
NO
The following can cause the
heater to shut down:
* Improper grounding.
* High winds.
* Taking combustion air from the
attic.
* Dirty environment.
* Baffle improperly positioned.
* Fluctuating gas pressure.
Does heater stay on until
call for heat ends?
YES
Troubleshooting ends.
Check to make sure gas pressure is within
minimum and maximum inputs, as indicated
on AGA burner rating label. Is gas pressure
OK?
If heater does not go into high-fire mode, check the following:
Check power across the green and black
wires of the yellow control cord. Is the
power 24V?
NO
Repair or replace faulty
wiring or thermostat.
The relay board is
faulty and must be
replaced.
Measure the voltage
across the red wire
on the relay board
and GND on the
circuit board. It
there 24V?
The valve is faulty and
must be replaced.
YES
NOTE: To confirm the heater is not in high-fire mode, check the manifold
pressure. If 3.5” natural or 10” propane, the light is faulty and should be
replaced. If approximately 2.0” to 2.5” natural or 5.0” to 6.5” propane,
the heater is in low-fire mode and the troubleshooting steps described
here should be followed.
NO
YES
*
WARNING:
Bypassing any switch
is for testing purposes
only. Do not leave
switch bypassed during
normal operation or
heater’s built-in safety
mechanisms will be
compromised.
*
*
See page 7 for fault
flash code signals.
NO
