Troubleshooting Unit - Greenheck ERCH-20 Installation, Operation And Maintenance Manual

Troubleshooting – Unit
Symptom Possible Cause
Blown fuse or open circuit breaker.
Defective motor or capacitor.
Blower fails to
Motor overloaded.
operate
Electrical.
Control power (24 VAC) wiring run is too
long. (Resistance should not
exceed 0.75 ohms).
Motor starters
"chatter" or do
Incoming supply power is less than
not pull in
anticipated. Voltage supplied to starter coil
must be within +10% / -15% of nominal
voltage stated on the coil.
Static pressures are higher than design.
Motor voltage incorrect.
Motor over
amps
Motor horsepower too low.
Shorted windings in motor.
Unit damper not fully open.
System static pressure too high.
Blower speed too low.
Low airflow
Fan wheels are operating backwards.
(cfm)
Dirty filter.
Leaks in ductwork.
Elbows or other obstructions may be
obstructing fan outlet.
Blower fan speed too high.
High airflow
Filter(s) not in place.
(cfm)
Insufficient static pressure (Ps).
(airflow resistance)
Fan wheel rubbing on inlet.
Bearings.
Excessive
noise or Loose wheel on shaft.
vibration
Motor base or blower loose.
Noise being transmitted by duct.
Always have a completed Pre-Start-Up Checklist and Start-Up Checklist prior to requesting parts or service
information.
46 Energy Recovery Ventilator with Heating and Cooling General Description - NOT model specific
Corrective Action
Replace fuse or reset circuit breaker and check amps.
Replace.
Reset VFD and check amps.
Check for On/Off switches. Check for correct supply voltage.
Check Control wiring.
Shorten wiring run to mechanical room or install a relay to turn
unit on/off. Consult factory for relay information. Increase wire
gauge size so that resistance is 0.75 ohms or less.
Need to increase supply power or use a special control
transformer which is sized for the actual supply power.
Check for dirty filters. Improve ductwork.
Check motor wiring. Check motor nameplate versus supplied
voltage.
See specifications and catalog for fan curves to determine if
horsepower is sufficient.
Replace motor.
Adjust damper linkage or replace damper motor.
Improve ductwork to eliminate losses using good duct
practices.
Check maximum motor RPM and compare with catalog data.
Verify that external control wiring is in place if required.
For 3-phase, see Direction of Fan Wheel Rotation Direction in
Start-Up Components section.
Replace filters or follow cleaning procedures in Routine
Maintenance section of this manual.
Repair.
Correct or improve ductwork.
Check for correct maximum fan RPM. Decrease maximum fan
speed if necessary in the VFD.
Install filters.
Induce Ps into system ductwork. Make sure grilles and access
doors are installed. Decrease fan speed if necessary.
Adjust wheel and/or inlet cone. Tighten wheel hub or bearing
collars on shaft.
Replace defective bearing(s). Lubricate bearings. Tighten
collars and fasteners.
Tighten wheel hub.
Tighten mounting bolts.
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.
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