Greenheck Fan ERV-521, ERV-581 Troubleshooting Unit, Symptom Possible Cause Corrective Action

Troubleshooting – Unit

Symptom	Possible Cause	Corrective Action
	Blown fuse or open circuit breaker.	Replace fuse or reset circuit breaker and check
		amps.
	Defective motor or capacitor.	Replace.
Blower fails to
	Motor starter overloaded.	Reset starter and check amps.
operate
	Electrical.	Check for On/Off switches. Check for correct
		supply voltage.
	Drive.	Check for broken or loose belts. Tighten loose
		pulleys.
	Control power (24 VAC) wiring run is too long	Shorten wiring run to mechanical room or
		install a relay which will turn unit on/off. Consult
Motor starters	(resistance should not exceed 0.75 ohms).
		Factory for relay information.
“chatter” or
	Incoming supply power is less than anticipated.	Need to increase supply power or use a special
do not pull in
	Voltage supplied to starter coil must be within	control transformer which is sized for the actual
	+10% / -15% of nominal voltage stated on the coil.	supply power.
	CFM too high.	Check cfm and adjust drives if needed.
	Static pressures are higher or lower than	If higher, ductwork should be improved.
	design.	If lower, fan rpm should be lower.
	Blower rotation is incorrect.	Check rotation and reverse if necessary.
Motor over amps
	Motor voltage incorrect.	Check motor nameplate versus supplied
		voltage.
	Motor horsepower too low.	See specifications and catalog for fan curves to
		determine if horsepower is sufficient.
	Shorted windings in motor.	Replace motor.
	Unit damper not fully open.	Adjust damper linkage or replace damper motor.
	System static pressure too high.	Improve ductwork to eliminate losses using
		good duct practices.
	Blower speed too low.	Check for correct drives and rpm with catalog
		data.
	Fan wheels are operating backwards.	For 3-phase, see Direction of Fan Wheel
Low airflow (cfm)		Rotation under Unit Start-Up section.
	Dirty filter or energy wheel.	Follow cleaning procedures in Routine
		Maintenance section.
	Leaks in ductwork.	Repair.
	Elbows or other obstructions may be	Correct or improve ductwork.
	obstructing fan outlet.
	Belt slippage.	Adjust belt tension.
	Blower fan speed too high.	Check for correct fan rpm. Decrease fan speed
		if necessary.
High airflow (cfm)	Filter(s) not in place.	Install filters.
	Insufficient static pressure (Ps) (airflow	Induce Ps into system ductwork. Make sure
		grilles and access doors are installed. Decrease
	resistance).
		fan speed if necessary.

Always have a completed Pre Start-Up Checklist, unit Start-Up Checklist, and Optional Accessories Checklist prior to requesting parts or service information.

Model ERV Energy Recovery Unit 33