Specifications

– 29 –
Symptom Cause Remedy
B. No voltage at flame
safeguard relay input
terminals.
1. Fan and Heat "off-on"
switch in "off" position.
2. SW-13 in MT-11 (if applicable)
not closed.
3. Auxiliary switch on starter
not closed.
4. Proof of closure switch open
(if applicable).
5. Thermostat open.
6. High temperature limit is open.
7. High-Low gas pressure
switches open.
8. Outside air temperature
higher than on-off inlet
ductstat setting.
9. Time clock or field installed
controls open.
1. Place switch in "on"
position.
2. Check modulating motor for
proper operation (see sheet in
manual).
3. Check auxiliary circuit wiring
and contacts.
4. Check and see if gas valve
is closed, check wiring on
circuit.
5. Check thermostat for proper
setting.
6. Check limit for proper
settings.
7. Correct gas pressure and reset
switches.
8. Check ductstat for proper
setting.
9. Check time clock and field
controls for correct settings
and voltage.
SECTION VII - TROUBLESHOOTING continued
C. Flame safeguard relay
goes into safety
shutdown (Lockout).
1. See technical data sheets on
flame safeguard relay.
1. Determine the cause of
lockout. Push reset button on
flame safeguard relay.
D. Pilot does not light after
pre-purge has timed out
and voltage is present on
flame safeguard output
terminals.
1. Manual pilot shut-off valve
closed.
2. Inlet gas pressure lower than
minimum gas pressure
required.
3. No gas through pilot regulator
with sufficient inlet gas
pressure.
4. No gas flow through pilot
solenoid valve.
5. Type of gas supplied (natural
gas or propane) different than
shown on unit rating plate.
6. Flame detection system not
sensing pilot flame. (See
section for servicing burner).
7. No voltage on secondary side
of ignition transformer.
1. Slowly open valve.
2. Increase gas pressure.
3. Clear obstruction in vent
orifice or line, replace if
defective.
4. Check for proper installation,
and voltage. Correct or
replace if defective.
5. Connect to proper fuel supply
of contact factory for field
conversion parts.
6a. U.V. Sensor – Clean lens,
check wiring and spark rod.
6b. Flame Rod - Assure rod is in
pilot flame, check wiring, and
flame rod.
7. Check wiring. Replace
transformer if defective.