I have a Arcoaire Model# N2H336GKA100 setup with dual fuel for a gas furnace that has started to make what I would call a "whistling" noise when the unit is in Heat Mode. When it's running in Cool mode it sounds normal without any issues. I installed this unit my self back in 2003 i think, I'm still looking for the paper work. My background is transport refrigeration so I'm pretty comfortable working with this. I'm just not familiar with residential equipment.
It almost sounds like it might be the reversing valve is not shifted properly and the whistling sound is the refrigeration leaking by. The unit still seems to heat ok but I'm currently running the the unit in Emergency Heat so i dont drive the neighbors crazy. I've attached a link to a mp3 file you can listen to. I recorded this with my phone so you may need to turn up the volume. The noise is constant and doesn't seem to get any louder or quieter with time.
I have eliminated the condenser fan by disconnecting it and the noise is still present and i hooked my gauges to the unit and its about 40 degrees here and the liquid line was around 55 psi and the gas line was around 190 psi in heat - R22.
I would appreciate any advice you experts can offer.
Tried turning it on defrost yet to see if the sound is still there? Energizing and de-energizing the reversing valve several times yet to confirm it slides? Cecked BTU output to confirm the internal relief valve in the compressor isn't stuck partially open?