I have a Trane Air handler unit (AHU): 4TEE3F40A. I found the AC ran continuously last two days and indoor temperature were still above 85F. Today, I open the AHU and found the coil freezed with ice. It seems that an ICM fan runs at low speed. Could you tell me how to increase/adjust the fan speed? Dip switch setting are correct.

Thanks in advance.

Lixing

Lixing - ((.( % of the time when they freeze up like this ,IT IS CAUSED FROM BEING LOW ON FREEON, You need to call a service man and have ity checked. Good luck and have a nice day and GOD BLESS :: F.B.E.

I have a Trane Air handler unit (AHU): 4TEE3F40A. I found the AC ran continuously last two days and indoor temperature were still above 85F. Today, I open the AHU and found the coil freezed with ice. It seems that an ICM fan runs at low speed. Could you tell me how to increase/adjust the fan speed? Dip switch setting are correct.

Thanks in advance.

Lixing
Check your filters, sounds like a restiction on your return air.

You do not want to mess with the dip switches. They are set using a professional to for proper air flow and if that motor is a variable speed unit with a electronic end bell that could set you back a cool 950.00 easy if you mess it up.

I would call a professional for a ON SITE inspection of your problem before it ends up costing you more $$.

Flying Blue Eagle:

Thanks for your quick answer. My concern is that if less freon, the coil should not be frozen. Is my understanding correct. I definitely will call a service man to check.

Lixing

It is possible a refrigerant/freon loss will show up as a frosted/frozen coil but not always. Many other factors can come into play. Air flow, and refrigerant restrictions are just two other examples that can cause the same problem.

Under normal operating conditions a indoor coil should not freeze or frost over.