Greenheck Fan HEAT RECOVERY UNIT WITH EVAPORATIVE COOLING HRE-20 - Manual (Page 43)

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* Always provide the unit model and serial number when requesting parts or service information. * Always check motor amps and compare to nameplate rating.
Control power (24 Vac) wiring
run is too long (resistance
should not exceed 0 .75 ohms) . Shorten wiring run to mechanical room or install a relay
which will turn unit on/off (C/F for relay information) .
Incoming supply power is
less than anticipated . Voltage
supplied to starter coil must
be within +10% / -15% of
nominal voltage stated on
the coil . Need to increase supply power or use a special control
transformer which is sized for the actual supply power .
Motor Starters
‘Chatter’
or
Do Not Pull In
Blown fuse or open circuit
breaker . Replace fuse or reset circuit breaker and check amps .
Possible Cause Symptom Corrective Action
Defective motor or capacitor . Replace .
Motor starter overloaded . Reset starter and check amps .
Electrical . Check for On/Off switches . Check for correct supply voltage .
Drive . Check for broken or loose belts . Tighten loose pulleys .
Blower Fails to
Operate
Cfm too high . Check cfm and adjust drives if needed .
Static pressures are higher or
lower than design . If higher, ductwork should be improved .
If lower, fan rpm should be lower .
Blower rotation is incorrect . Check rotation and reverse if necessary .
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 .
Motor Over Amps
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 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 obstructing fan outlet . Correct or improve ductwork .
Belt slippage . Adjust belt tension .
Blower fan speed too high . Check for correct fan rpm . Decrease fan speed if necessary .
Filter(s) not in place . Install filters .
Insufficient static pressure (Ps)
(airflow resistance) . Induce Ps into system ductwork . Make sure grilles and
access doors are installed . Decrease fan speed if necessary .
Low Airflow (cfm)
High Airflow (cfm)
Troubleshooting