| Troubleshooting Chart for ECM Variable Speed Air Circulator Blower Motors | SERVICING | |||
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Symptom | Fault Description(s) | Possible Causes | Corrective Action | Cautions and Notes |
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- Motor rocks | - This is normal |
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slightly |
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variable speed motor. |
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when starting. |
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| - Manual disconnect switch off or | - Check 230 Vac power at motor. |
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| door switch open. | - Check low voltage (24 Vac R to C) at motor. | - Turn power OFF prior to repair. |
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| - Blown fuse or circuit breaker. | - Check low voltage connections |
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| Wait 5 minutes after |
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| - 24 Vac wires miswired. | (G, Y, W, R, C) at motor. |
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| - No movement. | disconnecting power before |
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| - Unseated pins in wiring | - Check for unseated pins in connectors |
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| opening motor. |
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| harness connectors. | on motor harness. |
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- Motor won't |
| - Handle electronic motor/control with care. |
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| - Bad motor/control module. | - Test with a temporary jumper between R - G. |
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start. |
| - Moisture present in motor or control module. | - |
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| - Loose motor mount. | - Check for loose motor mount. | - Turn power OFF prior to repair. |
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| Wait 5 minutes after |
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| - Motor rocks, | - Make sure blower wheel is tight on shaft. |
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| - Blower wheel not tight on motor shaft. | disconnecting power before |
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| but won't start. | - Perform motor/control replacement check, |
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| - Bad motor/control module. | opening motor. |
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| ECM motors only. |
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| - Handle electronic motor/control with care. |
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- Motor |
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oscillates up & | - It is normal for motor to |
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down while | oscillate with |
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being tested | no load on shaft. |
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off of blower. |
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| - Variation in 230 Vac to motor. | - Check line voltage for variation or "sag". |
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| - Unseated pins in wiring harness | - Check low voltage connections |
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| - Varies up and down | connectors. | (G, Y, W, R, C) at | - Turn power OFF prior to repair. |
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| - Erratic CFM command from | motor, unseated pins in motor |
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| or intermittent. |
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| "BK" terminal. | harness connectors. |
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- Motor starts, |
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| - Improper thermostat connection or setting. | - |
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but runs |
| - Moisture present in motor/control module. | - Perform Moisture Check.* |
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erratically. |
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| - Does removing panel or filter |
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| - "Hunts" or "puffs" at | - Incorrect or dirty filter(s). | reduce "puffing"? |
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| - Incorrect supply or return ductwork. | - Check/replace filter. | - Turn power OFF prior to repair. |
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| high CFM (speed). |
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| - Incorrect blower speed setting. | - Check/correct duct restrictions. |
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| - Adjust to correct blower speed setting. |
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*Moisture Check
-Connectors are oriented "down" (or as recommended by equipment manufacturer).
-Is condensate drain plugged?
-Check for undercharged condition.
-Arrange harnesses with "drip loop" under motor.
-Check for low airflow (too much latent capacity).
-Check and plug leaks in return ducts, cabinet.
Note: You must use the correct replacement control/motor module since they are factory programmed for specific operating modes. Even though they look alike, different modules may have completely different
functionality. The ECM variable speed motors are c
Important Note: Using the wrong motor/control module voids all product warranties and may produce unexpected results.
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