Troubleshooting
The following tables list causes and corrective actions for possible problems with direct fired heater units. Review these lists prior to consulting manufacturer.
Airflow Troubleshooting Chart
Problem | Potential Cause | Corrective Action |
Fan Inoperative | Blown fuse or open circuit breaker | Replace fuse or reset circuit breaker |
|
| and check amps |
| Disconnect switch in “Off” position | Turn to “On” position |
| Motor wired incorrectly | Check motor wiring to wiring diagram |
|
| located on fan motor |
| Broken fan belt | Replace belt |
| Motor starter overloaded | Reset starter and check amps |
| Remote panel set to “Off” Position | Set Remote Panel to “Manual” or |
|
| “Auto” Position |
Motor Overload | Fan rotating in the wrong direction | Be sure fan is rotating in the direction |
|
| shown on rotation label |
| Fan speed is too high | Reduce fan RPM |
| Motor wired incorrectly | Check motor wiring to wiring diagram |
|
| located on fan motor |
| Overload in starter set too low | Set overload to motor FLA value |
| Motor HP too low | Determine if HP is sufficient for job |
| Duct static pressure lower than design | Reduce fan RPM |
Insufficient Airflow | Fan rotating in the wrong direction | Be sure fan is rotating in the direction |
|
| shown on rotation label |
| Poor outlet conditions | There should be a straight clear duct |
|
| at the outlet |
| Intake damper not fully open | Inspect damper linkage and replace |
|
| damper motor if needed |
| Duct static pressure higher than | Improve ductwork to eliminate or |
| design | reduce duct losses |
| Blower speed too low | Increase fan RPM. Do not overload |
|
| motor |
| Supply grills or registers closed | Open and adjust |
| Dirty or clogged filters | Clean and/or replace |
| Belt slippage | Adjust belt tension |
Excessive Airflow | Blower speed to high | Reduce fan RPM |
| Filters not installed | Install filters |
| Duct static pressure lower than design | Reduce fan RPM |
Excessive Vibration and Noise | Misaligned pulleys | Align pulleys |
| Damaged or unbalanced wheel | Replace wheel |
| Fan is operating in the unstable region | Refer to performance curve for fan |
| of the fan curve |
|
| Bearings need lubrication or | Lubricate or replace |
| replacement |
|
| Fan speed is too high | Reduce fan RPM |
| Belts too loose, worn or oily | Inspect and replace if needed |
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