116
Airflow Troubleshooting Chart
Problem
Potential Cause
Corrective Action
Fan Inoperative
Blown fuse/Open circuit breaker
Replace fuse or reset circuit breaker and
check amps.
Disconnect switch in “Off” position
Turn to “On” position.
Door switch
Verify door is closed properly.
Check door switch wiring and switch.
Motor wired incorrectly
Check motor wiring to wiring diagram
located on fan motor.
Motor starter overloaded
Reset starter and check amps.
HMI set to “Blower Off”
Set HMI to “Blower On.”
Motor Overload
Fan rotating in the wrong direction
Verify fan is rotating in the direction
shown on rotation label.
Fan speed is too high
Reduce fan RPM.
Motor wired incorrectly
Check motor wiring to wiring diagram
located on fan motor.
Check the fan wiring.
Check fan rotation using the HMI.
Overload in starter set too low
Set overload to motor FLA value.
Motor HP too low
Determine if HP is sufficient for job.
Duct static pressure lower than design Reduce fan RPM.
Insufficient Airflow
Fan rotating in the wrong direction
Verify fan is rotating in the direction
shown on rotation label.
Check the fan wiring.
Check fan rotation using the HMI.
Poor outlet conditions
There should be a straight clear duct at
the outlet.
Intake damper not fully open
Inspect damper linkage and replace
damper motor if needed.
Duct static pressure higher than design Improve ductwork to eliminate or reduce
duct losses.
Fan speed too low
Increase fan RPM. Do not overload
motor.
Indoor coil dirty or frozen
Clean Indoor Coil and filters.
Supply grills or registers closed
Open and adjust.
Dirty or clogged filters
Clean and/or replace.
Excessive Airflow
Fan speed to high
Reduce fan RPM.
Filters not installed
Install filters.
Duct static pressure lower than design Reduce fan RPM.
Excessive Vibration
and Noise
Fan speed is too high
Reduce fan RPM.
Damaged or unbalanced wheel
Replace wheel.
Fan is operating in the unstable region
of the fan curve
Refer to performance curve for fan.
Bearings need lubrication or
replacement
Lubricate or replace.