Applied Air GAS-FIRED HEATERS, Installation & Operation Instruction

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Symptom Cause Remedy
B. No voltage at fl ame
safeguard relay input
terminals (RE-02).
1. Heat Mode is disabled.
2. Incorrect
setpoint.
3. DO-2 or RE-28 is not energized.
4. Auxiliary switch on starter
not closed.
5. Air fl ow switch open.
6. RE-27, RE-56 and/or RE-65
contacts open.
7. Proof of closure switch open
(if applicable).
8. High temperature limit is open.
9. High-Low gas pressure
switches open.
10. Outside air temperature
higher than heating economizer
setpoint.
1. Enable the heating mode.
2. Check for proper setting.
3. See digital control system user
manual.
4. Check auxiliary circuit wiring
and contacts.
5. Check for proper CFM. Adjust
and/or replace switch.
6. See multiplexed voltage value
chart.
7. Check and see if gas valve
is closed, check wiring on
circuit.
8. Check limit for proper
settings.
9. Correct gas pressure and reset
switches.
10. Check for proper setpoint.
SECTION VII - TROUBLESHOOTING WITH DDC CONTROLS
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.