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airheatman, HVAC Technician
Category: HVAC
Satisfied Customers: 8326
Experience:  Furnace, A/C and heat pump specialist.
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We have a new 3.5 ton york hvac unit that works well but

Customer Question

we have a new 3.5 ton york hvac unit that works well but every time the air handler fan comes on it kills about half the stations we get on television the the techs came and decided it was the fan doing it they changed the fan and it still does it theychanged the fan motor to one that is controlled by solenoid or relay that cured the problem we had as long as the a/c was running it also worked well enough as long as the heat pump could keep it warm we live in ky and it dropped to 11 degrees when the auxiliary heat tried to kick in the fan shut off the tech came out and hot wired the fan to run all the time so we could have heat this is not acceptable do you have any ideas
Submitted: 8 months ago.
Category: HVAC
Expert:  airheatman replied 8 months ago.

What is model on the air handler?

Expert:  airheatman replied 8 months ago.

The problem is rare but not totally uncommon. The issue is caused by harmonic distortion being introduced into the AC power lines. This is caused by the non-sinusoidal current draw by the ECM motor. The DC power supply of the motor pulls power from the AC line in two sets of pulses at each AC peak, rather than in a smooth sinusoidal manner, as with a conventional PSC motor.

The normal solution is to install a choke in the motor hot lead,

Ask your installer to contact his York rep as to the proper choke he should install.

If unit already has a choke, have him replace it.

See link below for more information