28
Model PV
e
Heat Recovery Unit
Troubleshooting – Unit
Always have a completed Pre Start-Up Checklist, unit Start-Up Checklist, and Optional Accessories Checklist prior to requesting parts or
service information.
Symptom
Possible Cause
Corrective Action
One or both
blowers turn off
intermittently and
back on after
about 2 minutes
Exhaust Only frost control sensors are tripping.
Adjust frost temperature sensor set point as
needed.
Excessive noise
or vibration
Fan wheel rubbing on inlet.
Adjust wheel and/or inlet cone. Tighten wheel
hub or bearing collars on shaft.
Bearings.
Replace defective bearing(s). Lubricate
bearings. Tighten collars and fasteners.
Wheel out of balance.
Replace or rebalance.
Loose wheel on shaft.
Tighten wheel setscrew.
Loose motor or blower sheave.
Tighten sheave setscrew.
Belts too loose.
Adjust belt tension after 24 hours of operation.
Belts too tight.
Loosen to maintain a 3/8 inch deflection per
foot of span between sheaves.
Worn belt.
Replace.
Motor base or blower loose.
Tighten mounting bolts.
Buildup of material on wheel.
Clean wheel and housing.
Bearing and drive misaligned.
Realign.
Noise being transmitted by duct.
Make sure ductwork is supported properly.
Make sure ductwork metal thickness is sized for
proper stiffness. Check duct size at discharge to
ensure that air velocities are not too high.
