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I live in North Carolina and recently moved into a 1981 home. The TRANE heat pump outside is about four years old. The inside unit appears to be original. It is a large, brown, aluminum unit, with an inspection sticker dated 8-80. It has a General Electric Label and the model number field is blank.
On cold night, when the furnace comes on, it rapidly cycles on and off about every 1-2 seconds. The unit inside makes a loud clicking and thumping noise and the fan out side momentarily stops running. Sometimes it stops on its own, sometimes we can turn the thermostat off then back on and this will stop it. It only seems to happen at night and it getting progressively worse. A friend mentioned there may be a bad switch that isn’t closing properly. I’m trying to find ideas so when the contractor comes to visit I won’t end up buying an unnecessary $2,000 furnace. However, 20 years is a long time and we it may be time to move on. Any Ideas?!?!?
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Brent - - Several years back, Trane, which is owned by American Standard, purchased the GE line of air conditioning products, so your original heat pump was probably all GE and the local Trane contractor replaced it because of Trane's close association with GE products.
It is a bit unclear as to what your exact problem may be, but it appears that there is some control problem with the heat pump cycle in colder weather. The heat pump cycle is only supposed to operate down to outside temperatures of around 40 degF or so, below which, the outside coil would tend to freeze up. Below these temperatures, the unit should go into the Auxilliary or Emergency heat mode, which is strictly electric resistance heat. The compressorized heat pump cycle will remain de-energized until it warms up outside.
From what you've indicated, there may be a control problem in the refrigeration system that needs repair. A low limit switch on the suction side of the compressor or something of that nature. Inadequate refrigerant may also cause these conditions. Does the unit cool adequately during warmer periods and warm adequately during moderate outdoor temperatures between 40 and 60 degF? If so, your compressor is probably operable, if not, the compressor may need checking out. In the cooling mode, do you see ice building up on any of the exposed copper piping from the indoor coil to the outdoor coil?
With regards to the indoor furnace, 17 years is getting a bit old, but as long as you don't have any major repairs or begin experiencing refrigerant leaks, keep it running. A new unit will probably be more efficient, but the savings in energy isn't usually enough to get a quick return on investment until you have a major repair bill that can be avoided by the purchase of a new unit. At the first sign of refrigerant leaks, consider replacement since most coils wear pretty evenly and more leaks are on the way.
*Thanks Walter, The unit does cool and heat well during moderate temps. Only in the night does it do this, and even then, it still heats well. It just makes this terrible clicking and stop/start cycle. We are waiting on the contractor to arrive.Thanks for the response!
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I live in North Carolina and recently moved into a 1981 home. The TRANE heat pump outside is about four years old. The inside unit appears to be original. It is a large, brown, aluminum unit, with an inspection sticker dated 8-80. It has a General Electric Label and the model number field is blank.
On cold night, when the furnace comes on, it rapidly cycles on and off about every 1-2 seconds. The unit inside makes a loud clicking and thumping noise and the fan out side momentarily stops running. Sometimes it stops on its own, sometimes we can turn the thermostat off then back on and this will stop it. It only seems to happen at night and it getting progressively worse. A friend mentioned there may be a bad switch that isn't closing properly. I'm trying to find ideas so when the contractor comes to visit I won't end up buying an unnecessary $2,000 furnace. However, 20 years is a long time and we it may be time to move on. Any Ideas?!?!?