15
TROUBLESHOOTING
Continued
OBSERVED PROBLEM POSSIBLE CAUSE REMEDY
No heat (continued) 7. Blower not operating 7. A. Check power supply to furnace.
B. Check electrical connections at furnace.
C. With thermostat points closed, check for circuit
completion at motor. If voltage is present,
replace motor. If no voltage is present at
motor, check for:
• 24 volts on secondary coil or transformer. If no
voltage, replace transformer.
• If 24 volt transformer okay, check for circuit
completion across contacts on time delay
relay. Allow three to five seconds for contact to
close.
• If circuit across contacts okay, check conti-
nuity of wiring in motor circuit.
8. Short cycling (motor goes on and off) 8. A. Check thermostat. Contacts should remain
closed. If contacts are breaking:
• Check thermostat anticipator setting. It should
be between .75 and 1.0.
• If anticipator setting okay, check amp draw
across thermostat. If amp draw exceeds .65,
check amp draw across coil of valve and time
delay relay. Note: On initial operation of glo-
bar, there is a momentary surge of
approximately 4.0 amps.
• If amp draw is within limits, check for shorts in
thermostat wiring.
• If wiring is okay, replace thermostat.
IGNITION FAILURES
WARNINGS:
• Never connect unit or ignition
circuit to 230 volts.
• Never operate unit with glo-bar
touching burner or any other
ground. Damage to ignition
control will occur.
• Be sure sensor probe never
touches glo-bar. This will damage
ignition control.
• If the ignition control is defective,
it must be replaced. It is not field-
repairable.
CAUTION: Do not attempt to
repair the ignition control. This may
alter it and cause it to operate
incorrectly.
The electronic system is made up of two
parts: the ignition control and the glo-bar.
The ignition control is the brain of the
electronic system. It has several
functions:
1. When the blower reaches full r.p.m., a
24-volt circuit is completed to the
ignition control. (Check across yellow
and green wires.)
2. The white and blue wires at the ignition
control are the 120-volt input for the
glo-bar circuit. When the 24-volt circuit
is completed, the ignition control will
complete the 120-volt circuit to the glo-
bar and it begins to glow. (Check this
circuit across the two white wires at
the ignition control.)
3. After approximately 20 seconds, a 24-
volt circuit is completed through the
ignition control to the gas valve. (This
circuit is checked from brown wire at
ignition control to a neutral ground.)
This circuit opens the valve, gas flows
to the burner and is ignited by the heat
from the glo-bar. Note: Glo-bar
remains on.
4. When the burner flame is established,
the sensing probe will sense the
presence of burner flame and open the
glo-bar circuit. The glo-bar will then
stop glowing.
It is important to determine the type of
problem being experienced. Then the
proper checkout procedure can be made.
The following is a list of problems, how to
identify in which area the problem is
located, and how to correct it.
16
TROUBLESHOOTING
Continued
OBSERVED PROBLEM POSSIBLE CAUSE REMEDY
Ignition failures 1. Glo-bar will not glow - with blower run-
ning and microswitch engaged
1. Check the following:
A. Check for 24 volts A.C. across yellow and
green wires at ignition control. If no voltage,
check microswitch and limit switch for circuit
completion as well as wiring and wiring
connections.
B. Voltage present across yellow and green
wires, check for 120-volt input to ignition
control across white and blue wires. If no
voltage, check wiring all the way back to
power supply.
C. 120 volts present across white and blue wires,
check for 120 volts across the two white wires
at ignition control. If no voltage, replace
ignition control.
D. Voltage present across the two white wires,
check wiring and wire connections to glo-bar.
E. If wiring and wire connections okay, replace
glo-bar. (Glo-bar broken)
2. Glo-bar glows but burner will not come
on
2. A. Check for voltage (24 volts A.C.) at valve 40
seconds after glo-bar begins to glow. If
voltage present but valve not opening, replace
valve.
B. If no voltage at valve, check brown wire at
ignition control for continuity and good
connection.
C. If wire and wire connections okay, replace
ignition control.
3. Glo-bar operating and gas valve open-
ing but burner will not light
3. A. Check gas flow through burner. If no gas is
coming through burner, check for obstruction
in gas line, main burner orifice, or main burner.
B. If thermostat okay, check for 24 volt A.C.
circuit completion across yellow and green
wires at ignition control. If no voltage, check
for circuit completion through limit switch and
microswitch.
C. If voltage is present at ignition control across
yellow and green wires yet burner continues
to go off, replace ignition control.
4. If the ignitor remains on after main
burner ignition or the valve chatters,
reverse the 120 volt A.C. connections
at the wall receptacle
4. A. If polarity is okay yet burner continues to go
off, check thermostat to be sure it is still
completing the valve circuit. If not, check for
excessive amp draw in valve circuit.
B. If thermostat okay, check for 24 volt A.C.
circuit completion across yellow and green
wires at ignition control. If no voltage, check
for circuit completion through limit switch and
microswitch.
C. Voltage present at ignition control across
yellow and green wires yet burner continues
to go off, replace ignition control
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