Applied Air GAS-FIRED HEATERS, Installation & Operation Instruction

Page: 40 / 64

– 40 –
Symptom Cause Remedy
B. No voltage at fl ame
safeguard relay input
terminals (RE-02).
1. Fan and Heat "off-on"
switch in "off" position.
2. SW-11/SW-13 in MT-11/MTR-4
(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 fi eld installed con-
trols 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 set-
ting.
6. Check limit for proper
settings.
7. Correct gas pressure and reset
switches.
8. Check ductstat for proper
setting.
9. Check time clock and fi eld con-
trols for correct settings
and voltage.
SECTION VII - TROUBLESHOOTING
continued
C. Flame safeguard relay
(RE-02) goes into safety
shutdown (Lockout).
1. See technical data sheets on
fl ame safeguard relay.
1. Determine the cause of
lockout. Push reset button on
fl ame safeguard relay.
D. Pilot does not light after
90 second pre-purge
has timed out and voltage
is present on fl ame
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 suffi cient inlet gas
pressure.
4. No gas fl ow 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 fl ame. (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
orifi ce 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 fi eld
conversion parts.
6a. U.V. Sensor – Clean lens,
check wiring and spark rod.
6b. Flame Rod - Assure rod is in
pilot fl ame, check wiring, and
fl ame rod.
7. Check wiring. Replace
transformer if defective.