Low airflow at minimum setting of 33%
- ECM motor requires a minimum static pressure to continue ramping up when high speed is required.
- Fan fails to maintain a minimum static pressure at current programed 33% minimum setting, due to different duct sizing / applications.
- When unit attempts to run compressor at 33% = Low Discharge Air Temp Alarm can occur.
- When unit attempts to run compressor at 33% = Required maximum (73%) capacity cannot be accomplished. Fails to meet T&B requirements.
- Suspect that when winter comes and calls for electric heat (External Boiler less Electric Heat), will result in over heating of electric strips will occur.
Maximum airflow setting of 73%
- Required maximum (73%) capacity cannot be accomplished. Fails to meet T&B requirements.
- This leads to beliefs that motors must be reprogrammed in the field.
- Latest reports that Service Parts has decided not to take any responsibility for programming ECM motors, resulting in the necessity to send all motors that need reprogramming, back to the factory.
Possible actions necessary to correct this issue
- Reprogramming of min and max settings at run-in stand.
- Suggestions on what new settings should be.