Troubleshooting
This section is intended to be used as a diagnostic aid only. For detailed repair procedures, contact your local Trane service representative.
WARNING Hazardous Service Procedures!
The maintenance and troubleshooting procedures recommended in this section of the manual could result in exposure to electrical, mechanical or other potential safety hazards. Always refer to the safety warnings provided throughout this manual concerning these procedures. When possible, disconnect all electrical power
including remote disconnects before servicing. Follow proper lockout/ tagout procedures to ensure the power can not be inadvertently energized. When necessary to work with live electrical components, have a qualified licensed electrician or other individual who has been trained in handling live electrical components perform these tasks. Failure to follow all of the recommended safety warnings provided, could result in death or serious injury.
Table 8. Air handler troubleshooting recommendations
Symptom | Probable Cause | Recommended Action |
Bearing is | First start after relubrication (grease distribution) | Allow machine to cool down and restart. |
excessively hot | Clean surface of grease and purge. | |
| Over tensioned belts | Adjust belt tension. |
| No lubricant | Apply lubricant. Check bearings for damage. |
| Misaligned bearing | Correct alignment. Check shaft level. |
Motor fails to start | Blown fuse or open circuit breaker | Replace fuse or reset circuit breaker. |
| Overload trip | Check and reset overload. |
| Improper wiring or connections | Check wiring with diagram supplied on unit. |
| Improper current supply | Compare actual supply power with motor nameplate |
|
| recommendations. Contact power company for adjustments. |
| Mechanical failure | Check that motor and drive rotate freely. Check bearing lubricant. |
|
|
|
Motor stalls | Open phase | Check line for an open phase. |
| Overloaded motor | Reduce load or replace with larger motor. |
| Low line voltage | Check across AC line. Correct voltage if possible. |
|
|
|
Excessive vibration | Poor alignment | Align bearing set screws (see Figure 49). Loosen and retighten |
|
| bearing set screws. |
| Bolts not removed. | Remove bolts (see the “Isolator Adjustment” section on page 24). |
| Over tensioned belts | Adjust belt tension. |
| Misaligned drive | Align drive. |
Motor runs and then | Partial loss of line voltage | Check for loose connections. Determine adequacy of main power |
dies down |
| supply. |
| Starter shorts when motor warms up | Replace starter. |
|
|
|
Motor does not come | Low voltage at motor terminals | Check across AC line and correct voltage loss if possible. |
up to speed | Line wiring to motor too small | Replace with larger sized wiring. |
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|
|
Motor overheats | Overloaded motor | Reduce load or replace with a larger motor. |
| Motor fan is clogged with dirt preventing proper | Remove fan cover, clean fan and replace cover. |
| ventilation |
|
Excessive motor | Motor mounting bolts loose | Tighten motor mounting bolts. |
noise | Rigid coupling connections | Replace with flexible connections. |
| Worn motor bearings | Replace bearings and seals. |
| Fan rubbing on fan cover | Remove interference in motor fan housing. |
|
|
|
Rapid motor bearing | Excessive overhung load due to overtensioned | Check belt tension and overhung load. |
wear | drive |
|
| Excessive overhung load due to a small diameter | Replace sheave with larger one. |
| motor sheave |
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|
|
|
Loose fan belt | Motor is poorly positioned | Adjust belt tension. |
| Worn or damaged belt | Replace belt or belt set. Check sheave alignment. |
| Worn sheaves | Replace sheaves. |
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56 |
