Bosch FHP RT-20 Installation, Operation And Maintenance Manual page 42

Troubleshooting – Unit
Symptom Possible Cause
Fan wheel rubbing on inlet.
Bearings.
Wheel out of balance.
Loose wheel on shaft.
Loose motor or blower sheave.
Belts too loose.
Excessive noise
Belts too tight.
or vibration
Worn belt.
Motor base or blower loose.
Buildup of material on wheel.
Bearing and drive misaligned.
Noise being transmitted by duct.
Always have a completed Pre Start-Up Checklist, unit Start-Up Checklist, and Optional Accessories Checklist prior to requesting parts or
service information.
42 Model RT Energy Recovery Unit
Corrective Action
Adjust wheel and/or inlet cone. Tighten wheel
hub or bearing collars on shaft.
Replace defective bearing(s). Lubricate bearings.
Tighten collars and fasteners.
Replace or rebalance.
Tighten wheel setscrew.
Tighten sheave setscrew.
Adjust belt tension after 24 hours of operation.
Loosen to maintain a 3/8 inch deflection per foot
of span between sheaves.
Replace.
Tighten mounting bolts.
Clean wheel and housing.
Realign.
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.