We had a Carrier heat pump/air handler installed in March. The installation people told us to keep the fan running all of the time to circulate air. Last night it started to make a high-pitched noise when just the fan was running, that could be heard through the registers in the house. You can't hear this sound when the air conditioning is running, only when the fan is running. My husband thinks it's a bad bearing, but the repairman doubts that and says he has to contact Carrier since he's never heard of this problem before. Has anyone out there heard of this and what do you think it might be? Thank you.

((We had a Carrier heat pump/air handler installed in March))

You are still under warranty. Let the company you bought the unit from contact Carrier Corporation.

((You can't hear this sound when the air conditioning is running, only when the fan is running. ))

This is a strange complaint because usually the additional noise is caused when the A/C is running not when just the fan is running.

Your husband might be correct because the motor is probably making the noise but why it would make the noise at one time and not the other is difficult to make sense of.

If you do not want to hear the noise set your thermostat to auto fan. This will prevent the inside blower motor from running when the A/C is not running.This is a temporary measure until the problem can be corrected.

Thanks for the input. Actually the day after I posted when I was in the basement while the A.C. was running, I could hear the noise coming from the air handler, but couldn't hear it upstairs through the registers like I can when the A.C. is off, perhaps due to the noise of the A.C. blower? We're still waiting to hear from the dealer--the repairman came on Monday and we've yet to hear anything. Thanks again!

Can you hear this noise through the return or supply registers?

We hear it mainly through the registers. Thanks!

I find this problem odd as well, usually when the fan is in the "on" position it is on high speed and it would run in high speed in air conditioning too. So shutting the A/C off shouldn't make a diffrence, Can you hear the noise from the furnace, or just the registers? My guess is that you have bad bearings, without seeing/hearing the problem myself, it's hard to say. Can you give me a little more info?

Thanks for the reply. My husband also thinks it's a bearing, but for some reason the repairman just thinks that we are crazy. We still haven't heard back from the dealer, so we're giving them one more day to hear from Carrier and then are just going to have to talk to the owner instead of the repairman and the secretary. Why they wouldn't want to fix it is beyond us. And as far as where the noise is from, when just the fan is running you can hear it through the registers and from the furnace, but when the A.C. is on, you hear it from the furnace and not through the registers, probably due to blower noise. Thanks for your replies!