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MUA-SVP01A-EN • Direct-Fired Indoor and Outdoor Units 35
Diagnostics
– Yes. Continue.
3. Is the unit enable relay energized?
– No. There is an open in the wiring between these terminals. Determine
cause and rectify.
– Yes. Continue.
4. Is the unit enable relay's normally open contact, closed?
– No. Replace relay.
– Yes. Continue.
5. Is the motor overload relay tripped?
– Yes. Determine cause, rectify and reset.
– No. Continue.
6. Is the motor starter energized?
– No. There is an open or break in the wiring. Determine cause and rectify.
– Yes. Check motor and motor wiring.
FAULT CODE: Check Airflow Switches
PROBLEM: The controller has activated the unit enable output to start the fan,
and detected that the fan is running from a signal at the fan status input.
Subsequently, the controller has detected a momentary opening of the fan status
input. The momentary opening must occur within two seconds of the previous
closure for this fault to occur. This fault requires the operator to correct the
condition and reset the alarm before normal unit operation resumes.
SOLUTION:If high airflow switch is opening. Do not adjust the switch
setpoints
1. Are all of the filters in place?
– No. Install filters and continue.
– Yes. Continue.
2. Does the external static pressure match that listed on the rating plate?
– No. Verify all associated ductwork is installed and continue.
– Yes. Continue.
3. Does the fan RPM match that listed on the Spec. Sheet?
– No. Correct to reduced fan speed and continue.
– Yes. Continue.
4. Are the airflow switches' sensing tubes obstructed?
– Yes. Clear and continue.
– No. Continue.
5. Contact factory.