44
FORSAIRE COUNTERFLOW DIRECT VENT GAS WALL HEATER
TROUBLESHOOTING YOUR FURNACE
ISSUE
1. No spark – no pilot gas.
2. Spark – but no pilot gas.
3. Pilot gas – but no spark.
4. Pilot lit, but main burner
won’t come ON.
POSSIBLE CAUSE(S)
A. No main power.
B. Faulty transformer.
C. Faulty thermostat.
D. Faulty limit switch.
E. Faulty ignition control.
F. Faulty wiring.
A. Faulty ignition.
B. No gas supplied to pilot valve.
C. Manual valves in OFF position.
D. Faulty pilot valve.
E. Faulty wiring.
F. Restricted pilot line or clogged
pilot orifice.
A. Faulty ignition control.
B. Broken or shorted electrode
assembly.
A. Faulty ignition control unit.
B. Faulty wiring.
C. Low pilot flame.
D. Improper alignment of
sensor in pilot flame.
CORRECTIVE ACTION
Perform normal system checks of the main power, transformer, thermostat,
limit switch, and replace faulty components.
With the power ON, turn the thermostat to the lowest setting, wait for 10
seconds and return to HIGH setting. With the power ON and thermostat set
at its highest position, set voltmeter to 24V scale and attach the probes to
terminals “TR” and “TH” on the ignition control unit.
If you read 24V and there still is no spark or pilot gas, the ignition control unit is
defective and must be replaced.
Test wiring. Repair or replace.
See 1E.
Check for availability of gas at gas control valve. Make sure the manual valve
(gas cock) on the gas control are in the full ON position. No pilot gas could be
caused by plugged pilot tubing. Also check the pilot adjustment at the gas
control valve.
See 1F.
See 2B.
With power ON, turn the thermostat to the lowest setting, wait for 10 seconds
and then return it to the high setting. With power ON and thermostat set at
its highest position, set voltmeter to 24V scale and attach probes to terminals
“TR” and “TH” on the ignition control unit. If you read 24V and there is still no
spark or pilot gas, the ignition control is defective and must be replaced. With
thermostat turned to its highest setting, set test meter to 24V scale. Touch
probes to “C” and “P” terminals on the Gas Control Valve. If you do not get a
24V reading, check wiring. If wiring tests okay, check the ignition control unit.
Remove wire at “COM” terminal at the ignition control unit, being careful
not to touch any metal parts; disconnect the electrode wire at the ignition
control unit. Connect one end of a jumper wire to terminal “GND”. (DO NOT
REMOVE EXISTING WIRE.) Attach the other end of the jumper wire to the
metal blade of a small screwdriver. Position the end of metal blade approx.
1/8” from the “HIGH VOLTAGE” (IGN) terminal. Reconnect the “COM” terminal.
Sparking should occur between the screwdriver blade and the “HIGH
VOLTAGE” terminal.
If no sparking occurs, the ignition control unit must be replaced.
Check the pilot and electrode assembly for proper electrode gap (3/32” to 1/8”)
or any possible shorting of electrode to surrounding metal surfaces. Make sure
the spark igniter and electrode connections to the ignition control unit are
tight. The ignition control unit and pilot burner must both be chassis ground.
If there is still no spark, the pilot and electrode assembly must be replaced.
See 3A.
See 1F.
NOTE: Wait at least 90 seconds after pilot lights before doing the check out
procedures for problem number 4. With the thermostat ON, be sure that the
pilot and sensor are properly aligned so that the pilot flame impinges the top
5/8 inch of the sensor. Be sure that the sensor is pushed all the way into the
pilot bracket. Adjust the pilot flame with pilot adjustment screw, if necessary.
Also check the inlet supply pressure and pilot orifice. If the pilot hood or sensor
is bent, the defective unit should be replaced. If the main burner still won’t
come ON, make sure the main burner orifices are clear. If orifices are clear,
set voltmeter to 24V scale and touch probes to the terminals of the main gas
operator on the gas valve. Touch probes to terminal “M”, “C” on Gas Valve. If you
read 24V and the burner won’t turn ON, replace entire gas valve.
When the main burner comes ON, ensure that the pilot flame is strong, the
sensor is properly aligned, and the pilot flame impinges the top 5/8 inch of
the sensor. (See procedures for checking proper pilot flame and alignment
in problem 4c.) Check the pilot and electrode assembly for proper electrode
gap (3/32” to 1/8”) or any possible shorting of electrode to surrounding metal
surfaces. Make sure the spark igniter and electrode connections to the ignition
FOR MODELS: 4007332 / 5507332 / 4007331 / 5507331
NOTE:
Before troubleshooting the intermittent pilot system, be sure thermostat is turned to highest setting, gas shut-off
valve and gas valve knob are in the ON position, and electric power is turned ON the furnace. Follow all steps in sequence.
A volt-ohm meter will be needed to satisfactorily determine if any components are malfunctioning.
