NOTICE
Bypassing any switch is intended for testing purposes only. Do not leave switch bypassed
during normal operation or the heater’s built-in safety mechanisms will be compromised.
Measure the voltage across
the red wire on the relay
board and ground on the
circuit board. Is there 24V?
17
4.0
Troubleshooting Guide
AG2
Series
Confirm that gas pressure is within maximum and minimum inputs
as indicated on the heater’s rating plate. Is gas pressure OK?
With a micrometer, check DC voltage at the
flame rod. Is it greater than 0.7 microamps?
Sensing rod is faulty or the flame is
too weak. Confirm that the heater is
operating at the proper gas pressure as
indicated on the heater’s rating plate.
Replace the sensing rod if necessary.
No
Yes
Confirm that the flame rod sensor wire is
okay; if so, replace the circuit board.
If the heater does not enter High Fire mode, check the following:
Check the power across the green
and black wires of the yellow
control cord. Is there 24V?
Yes
Repair or replace the faulty
wiring or thermostat.
Yes
The valve is
faulty and must
be replaced.
The relay board is faulty
and must be replaced.
No
No
NOTE: To confirm that the heater is not in high fire
mode, check the manifold pressure. If it is 3.5” (natural
gas) or 10” (propane), the indicator light is faulty and
should be replaced. If approximately 2.0” to 2.5”
(natural gas) or 5.0” to 6.5” (propane), the heater is in
low fire mode and the troubleshooting steps described
here should be followed.
Correct
problem.
No
Yes
Either there is a restriction
in the exhaust or the
pressure switch is faulty.
