Thread: Heat Pump Question

This is a one year old heat pump. When I got to the property, the heat pump was operating in normal mode. When I came around the rear of the house where the unit was located I noticed a lot of condensation streaming out of the base of the unit. Outside temperature was about 45 degrees.

I looked inside the unit and ice was barely forming on the refrigerant line. The unit was operating and when I walked away and the unit made an ugly (almost like a screech, but not real high pitched) noise like the compressor was coming on but with a vengeance (in addition to the operating sounds it was already making). The noise stopped and a few minutes later it made the noise again and then the unit sounded fairly normal. When I returned to the unit a few minutes later the refrigerant line inside the unit was iced over. When the unit kicked back off, the refrigerant line would thaw out. Is this normal?

If I understand correctly, heat pumps have a de-icing mode, but I have never seen it in play. Could this be what was happening? The heat pump was producing approximately 85 degree heat at the registers.

Eric

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If I read your description correctly, you have witnessed your first defrost cycle.
Come up a little farther north and you will see and hear it on a regular basis.

Originally Posted by Jim Luttrall

If I read your description correctly, you have witnessed your first defrost cycle.
Come up a little farther north and you will see and hear it on a regular basis.

Yep, I do agree.

Thanks Jim,

That is what I suspected. I don't see a whole lot of heat pumps around here, usually only out in areas where they haven't run the gas lines. I guess the outside temperature down here in the tropics typically hasn't been low enough (even in the winter) for the frosting to occur when I have operated these things.

Eric

Jim
I don't think I have ever been on the outside and heard a heat pump go into or out of a defrost cycle. What is the ugly screeching sound that Eric is talking about?

Does the compressor shut down while the reversing valve is changing modes?

If the compressor shuts down, is there a time delay built in before it starts up again?

Eric did not say what the inside house temperature was. If I was to assume 72 or 73 degrees, would an 85 degree register temperature be normal in that area?

Thanks

Jeff Euriech
Peoria Arizona

The noise is the reversing valve switching and the pressures rapidly changing while the compressor is running.
Sometimes you will even get a little hiss when you switch between heat and cool with the system off (compressor not running) depending on the configuration of the particular system.

Time delay is normal just like on a standard a/c but does not come into play normally during defrost since the unit will be running.

85 would be within the realm of normal... but that is not a diagnostic tool as it is meaningless without other information.

There was a hiss. Also, when the fan kicked on I saw a spray mist blow out of the condensing unit. I was thinking that it was vaporized moisture from the condensating refrigerant pipes that had thawed being kicked up by the fan?

Interior temp was approx 70 degrees.

Eric

Thanks Jim

Jeff