Good morning. I had a Trane 13 SEER variable speed air handler installed earlier this year. The existing heat pump was used, which is a Unitary Products (?) unit rated at 10 SEER. Unit works great for air conditioning.
However, when we started using the heat I noticed a hum coming from the air handler. I narrowed it down to the suction line, so I had the contractor come back out and confirm. He heard the same noise, but unfortunately he left telling me there was nothing they can do (after claiming their main guy knows everything and if he don't know nobody knows). So, I got upset.
Since then, the noise has gotten progressively worse. Seems like the noise is related to the temperature outside (louder when colder). I want to call them back out here, but before I do I wanted to get some advice on this problem.
I have looked at past posts and saw other people having the same problem. The contractor did try moving linesets some, but he only checked pressures and temperature and gave up there. He didn't say anything about installing a muffler. To no surprise, he tried upselling me on a new compressor unit, but the unit I have outside is only 5 years old.
Most of the sound is eminating from the downstairs return duct, so I imagine the open space might be amplifying the sound. Is there anything I can do to try and fix this?
Would appreciate any help.