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gotoman for ac
gotoman for ac, HVAC Technician
Category: HVAC
Satisfied Customers: 5176
Experience:  51 years of experience install design and repair of all makes and models of AC
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A 4TTB3048D unit is making a stable, not modulating, howling

Customer Question

A 4TTB3048D unit is making a stable, not modulating, howling sound at approx 800 Hz. The sound starts right at the time when the unit starts up and ends when the unit shuts down. I do not expect that this is normal. By experience I would estimate this being beyond the 74dB specified at this frequency. I can send a sound sample if needed.
Submitted: 2 years ago.
Category: HVAC
Expert:  gotoman for ac replied 2 years ago.
Russ here. Welcome. I am here to help. Please do not rate until you are satisfied with answer. Always available for follow up questions. You can move the fan blade of condenser fan down about 1/4 inch and that will formally quiet unit down. This is a common problem with a few of the new trans units. Russ
Customer: replied 2 years ago.
Russ, thank you for your response. To understand your answer, could you please be a bit more specific. What do you mean with moving the condenser fan blade down: 1. loosening the set screws and the move the entire propeller down (away from motor/grille) on the motor shaft without changing the propeller itself. or 2. leaving propeller in place and bending the end (on outside diameter) of each fan blade down 1/4", and not changing the blade angle in motion direction, or 3. changing the angle of each blade (steeper or flatter) by moving the blade edge down either front or back side. Thank you. Thomas
Customer: replied 2 years ago.
Russ, a correction from my initial post describing the problem: The noise frequency is actually 240 Hz, not 800 Hz. Could this be a compressor noise indicating that the compressor might be about to fail or anything associated with the compressor? Thanks again Thomas
Expert:  gotoman for ac replied 2 years ago.
Sounds more like motor bearings. By moving fan blade just take set screw loose and move down about 1/4 inch. Russ
Customer: replied 2 years ago.
Russ, I have not had the chance to further check into the issue. Once I have moved the fan blade I will let you know whether it worked
Thomas