Troubleshooting - Greenheck HRE-20 Installation, operationand Maintenance Manual

Troubleshooting

Symptom Possible Cause
Blown fuse or open circuit
breaker .
Defective motor or capacitor .
Blower Fails to
Motor starter overloaded .
Operate
Electrical .
Drive .
Control power (24 Vac) wiring
run is too long (resistance
should not exceed 0 .75 ohms) .
Motor Starters
Incoming supply power is
'Chatter'
less than anticipated . Voltage
or
supplied to starter coil must
Do Not Pull In
be within +10% / -15% of
nominal voltage stated on
the coil .
Cfm too high .
Static pressures are higher or
lower than design .
Blower rotation is incorrect .
Motor Over Amps
Motor voltage incorrect .
Motor horsepower too low .
Shorted windings in motor .
Unit damper not fully open .
System static pressure too high
Blower speed too low .
Fan wheels are operating
backwards .
Low Airflow (cfm)
Dirty filter or energy wheel .
Leaks in ductwork .
Elbows or other obstructions
may be obstructing fan outlet .
Belt slippage .
Blower fan speed too high .
Filter(s) not in place .
High Airflow (cfm)
Insufficient static pressure (Ps)
(airflow resistance) .
* Always provide the unit model and serial number when requesting parts or service information. * Always check motor amps and compare to nameplate rating.
Corrective Action
Replace fuse or reset circuit breaker and check amps .
Replace .
Reset starter and check amps .
Check for On/Off switches . Check for correct supply voltage .
Check for broken or loose belts . Tighten loose pulleys .
Shorten wiring run to mechanical room or install a relay
which will turn unit on/off (C/F for relay information) .
Need to increase supply power or use a special control
transformer which is sized for the actual supply power .
Check cfm and adjust drives if needed .
If higher, ductwork should be improved .
If lower, fan rpm should be lower .
Check rotation and reverse if necessary .
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 for correct drives and rpm with catalog data .
For 3-phase, see Direction of Fan Wheel Rotation under Unit
Start-Up section .
Follow cleaning procedures in Routine Maintenance section .
Repair .
Correct or improve ductwork .
Adjust belt tension .
Check for correct fan rpm . Decrease fan speed if necessary .
Install filters .
Induce Ps into system ductwork . Make sure grilles and
access doors are installed . Decrease fan speed if necessary .
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