Form #43343530 –44– JJuly 08 Check external
thermostat wiring and
thermostat set point.
No
Yes
Remove red wire
from the Low fire
terminal, is there 24V
at the center C
terminal?
No
Yes
Is there 24V at the HI
terminal on the gas
valve?
No
Yes
With the thermostat
set to low fire only
does the low fire
amber light come on
after 15 seconds?
No
Yes
Is there 24V between
the thermostat
terminal block low fire
contact and ground?
No
Yes
Check terminal
connections, is the
yellow wire
connected to the high
fire terminal?
Check external
thermostat wiring and
thermostat set point.
Switch terminal
connections. Red wire
LO should be
connected to ignition
module W (TH)
terminal.
Repair terminal
connections. Restart
troubleshooting.
No
Yes
Are the black wires
to the amber light
securely on the gas
valve terminals?
Repair connection.
Restart
troubleshooting.
Replace amber light.
Restart
troubleshooting.
No
Yes
Does the low fire
amber light stay on
past 10 seconds?
No
Yes
Check the micro
Amps at the FC-FC+
terminals of the
module is it greater
than 0.7µA with flame.
Turn on the gas
valve?
Does LED on the
ignition module flash
three times?
Replace ignition
module.
Check flame sense
wire does it have
continuity?
Contact factory for
assistance.
Replace flame sense
wire.
Adjust terminal
connection. Restart
troubleshooting.
No
Yes
Is the knob on the gas
valve turned to the
ON position? No
Yes
Through the
inspection window is
there a flame visible
during start up?
No
Yes
Is the heater properly
grounded?
Correct grounding
problem.
No
Yes
Check the terminal on
the flame sense
electrode, is it tight?
No
Yes
Remove and inspect
flame sense
electrode. Is it clean
and the ceramic
intact?
Repair or replace
flame sense
electrode.
See next page for
troubleshooting
sequence.
No
Yes
Replace ignition
module.
No
Yes
No
Yes
Is there 24V at the HI
terminal on the gas
valve?
No
Yes
Does the high fire
amber light come on?
No
Yes
Is the there 24V
between the
thermostat terminal
block high fire contact
and ground (yellow
wire)?
No
Yes
Check terminal
connections to the
gas valve, are they
tight?
Check the red wires
C should be
connected to the TISS
and LO connected to
W (TH) module
terminal.
Repair terminal
connections.
Repair terminal
connections. Restart
troubleshooting.
No
Yes
Are the black wires
to the amber light
securely on the gas
valve terminals?
Repair connection.
Restart
troubleshooting.
Replace amber light.
Restart
troubleshooting.
Troubleshooting
continued on the next
page.