TROUBLE SHOOTING
Blower Unit
Symptom | Possible Cause | Corrective Action |
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Blower fails | Blown fuse or open circuit breaker | Replace fuse or reset circuit breaker and | ||
to operate |
| check amps |
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| Broken fan belt | Replace |
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| Defective motor or capacitor | Replace |
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| Motor starter overloaded | Reset starter and check amps |
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Motor overamps | CFMs too high | Check CFMs and adjust drives if needed |
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| Static pressures are higher or lower | If higher, ductwork should be improved | ||
| than design | If lower, fan RPMs should be lower |
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| Blower rotation is incorrect | Check rotation and correct | ||
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| Motor voltage incorrect | Check motor nameplate and supplied voltage |
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| Motor horsepower too low | See specifications and catalog for fan | ||
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| curves to determine if horsepower is sufficient. | ||
| Shorted windings in motor | Replace motor. |
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Insufficient airflow | Unit damper not fully open | Adjust damper linkage or replace | ||
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| damper motor |
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| System static pressure too high | Improve ductwork to eliminate losses | ||
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| using good duct practices |
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| Blower speed too low | Check for correct drives and RPMs | ||
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| with catalog data |
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| Dampers or registers closed. | Open and adjust |
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| Dirty or clogged filters | Clean or replace |
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| Leaks in ductwork. | Repair |
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| Elbows, or other obstructions | Correct or improve ductwork | ||
| may restrict fan outlet. | |||
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| Belt slippage | Adjust belt tension | ||
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Too much airflow | Blower fan speed too high | Check for correct fan RPM |
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| Filter(s) not in place. | Install filters | ||
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| Insufficient static pressure (SP) | Induce SP into system ductwork. | ||
| (airflow resistance) |
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Excessive noise | Wheel rubbing on housing | Center wheel | ||
or vibration |
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Loose wheel on shaft | Tighten wheel setscrew |
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| Loose motor or blower sheave | Tighten sheave setscrew |
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| Belts too loose | Adjust belt tension after 24 hours | ||
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| of operation |
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| Belts too tight | Loosen to maintain 3/8” deflection | ||
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| per ft. of span between sheaves |
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| Worn belt | Replace |
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| Motor base or blower loose | Tighten mountings bolts | ||
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| Worn bearings | Replace |
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| Bearing and drive alignment | Realign | ||
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| Motor out of balance | Replace |
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| Wheel out of balance | Replace or rebalance | ||
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| Sheaves eccentric or out of balance | Replace or rebalance | ||
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| Accumulation of material on wheel | Clean wheel and housing | ||
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