Irritating High Pitched Noise

[fred1949]

I've been trying to stop my Florida Heat Pump geothermal furnace from making this very high pitched sound while it is running. It sounds like a kids top that is spinning very fast. I've had the furnace repairman out 3 times & so far he has had no success in stopping the furnace noise. The furnace is model GOO48-1VTC. I've written FHP for suggestions & they replied with it might be the TXV valve or the HRP pump or maybe a loose heat strip. The repairman says that everything is OK, but he can hear the noise also. I've been here for 4 years & it just started making this noise this past winter. I think the furnace is about 14 years old. My furnace is on a loop system & is also connected to the water heater. Your help is really appreciated.

Thank you,
Fred

[HayZee518]

my thoughts about it is the thermo expansion valve being slow in opening. I worked on "Trane" air conditioners that used a sporlan TEX valve and when it throttles the freon, it makes that noise. sometime repositioning the superheat bulb on the cold supply line helps. when used with a heat pump the reversing valve doesn't open all the way and acts as a venturi or high pressure - low pressure orifice.

[fred1949]

Thank you

Thank you so much for the info. I will pass it on to the repairman.

Fred