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Phil, Mechanical Engineer
Category: HVAC
Satisfied Customers: 6022
Experience:  Retired HVAC/ Electrical & Boiler contractor. Industrial
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My Lennox CBX32MV air handler multi speed fan is only

Customer Question

My Lennox CBX32MV air handler multi speed fan is only running on low speed with a yellow light on the D52 Run space. What could be the cause.
Submitted: 1 year ago.
Category: HVAC
Expert:  HVAC Guru replied 1 year ago.

Hello, one minute while I get some information together.

Expert:  HVAC Guru replied 1 year ago.

Hello and thanks for using this service! If you are a JA Member I would like to personally thank you and welcome you back! I am HVAC Guru an extremely experienced tech on the site and I try to get to as many customers as I can. NOTE it takes time for me to type research and add links so please wait for me to respond back I can only do this so fast. Secondly, I do not know your skill level so please try and let me know if I am going beyond your knowledge or comfort zone thanks! I strive for a 5 star rating from everyone especially our JA members.

Are there any errors on the unit? Also are you sure it will never run faster?

Customer: replied 1 year ago.
The only error noted was the yellow light as mentioned before. The fan motor seems to run smoothly, just will not run up to a fast speed.
Customer: replied 1 year ago.
Is there a switch, transformer, etc. within the unit that controls the various speeds of the fan motor?
Expert:  HVAC Guru replied 1 year ago.

The speed is controlled by the board and it may not go high unless the demand is there for it as this is part of a board algorithm.

Customer: replied 1 year ago.
It is 81 degrees in the house and I set the ac at 72, so I am sure the demand it there. Can you be more specific as to the board or control switch that needs replacing?