32 Direct-Fired Indoor and Outdoor Units • MUA-SVP01A-EN
Diagnostics
2. Are the main automatic gas shutoff valves energized?
– No. The main automatic gas shutoff valves are leaking. Turn off unit and
close manual gas valves. Determine cause of valve failure and rectify.
– Yes. Continue.
3. Is the flame relay energized?
– No. There is a short in the wiring of the gas valves. Close manual gas
valves. Determine cause of short and rectify.
– Yes. Continue.
4. Is the burner enable relay energized?
– Yes. There is a short in the wiring of the flame relay. Close manual gas
valves. Determine cause of short and rectify.
– No. Continue.
5. Is the burner enable relay's normally open contact closed?
– Yes. Close manual gas valves. Replace the relay.
– No. Continue.
6. Unplug the input terminals from the input jack. Is there continuity at the
controller between the burner status terminals?
– No. Close manual gas valves. There is a short in the wiring between the
burner status relay and the burner status terminals. Determine cause and
rectify.
– Yes. Close manual gas valves. Replace the controller.
FAULT CODE: Flame Failure
Note: This fault code is not applicable to all unit types.
PROBLEM:The controller has received a signal from the flame relay
indicating a flame failure.
SOLUTION:Investigate flame relay
1. Is there a prior alarm such as Unit On/Fan Off, Airflow Sw., or Safety Circuit?
– Yes. See the Diagnostic section for the previous alarm.
– No. Continue.
2. See flame relay troubleshooting information in unit Installation, Operation,
and Maintenance Manual.
Diagnostics - Non-Critical Fault Codes
This section should assist the user in troubleshooting non-critical fault code
messages that have been displayed on the local user interface. Most of these
faults are automatically reset once the fault is corrected or condition changes.