Concern with HVAC cycling on and off when heat is on.

Old 11-29-19, 06:08 AM
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Concern with HVAC cycling on and off when heat is on.

Hi all,, I recently purchased a home in NC and this is my first week living in it. Source of heat is heat pump and I never owned a home with heat pump before. Now that is getting colder I noticed the compressor cycling on and off every 1sec non stop. So just wanted to check if this is a concern and if there is anything I should look at before calling the technicians. We also the inspection prior purchasing the home and there was no issues reported.

Home HVAC unit is all TRANE manufactured in 2014:
Thermostat Trane TCONT802AS32DAA
Compressor Trane 4TWB3036C1000AA
Air Handler Trane TEM3A0B36S31SAA

According to online research about cycling on and off issue could either be size of compressor/house or thermostat setting.
1- Compressor Size / Home Size: Home is a 1600 sqft home, HVAC unit been installed for more than 5 years so I am not really sure this could be the issue.
2 - Thermostat setting: Thermostat setting was set to cool before and we switched to heat. I am not sure of the exact configuration. Observation:
Thermostat Settings:
-- I looked into the thermostat settings and system type is set to "7 - 2 heat / 1 cool heat pump".
Thermostat Heat Mode:
-- when set to Heat - there is an aux heat next to the temperature set and this is when unit cycles on and off. It doesn't even seem to heat the house.
-- when set to EM Heat - there is no more cycling issues keeps running. Online sources says do not leave in this mode? You should only set your heat pump's thermostat to “emergency heat” when your heat pump stops heating altogether.

Any one have any experience or advice if there is something wrong or is just the wrong setting????

Old 11-29-19, 06:42 AM
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Sounds like you need a service call, unit should not be cycling that often and the emergency heat is for well, extreme conditions when normal heat is not sufficient.

Could be several reasons, bad thermostat, freon leak, control board! Not something easily diagnosed over a help forum!
Maki NG voted this post useful.
Old 11-29-19, 07:04 AM
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You have a mechanical or electrical issue. It shouldn’t cycle like that and can cause damage from prolonged short cycling.
Emergency heat can be extremely expensive to run depending on electric rates in your area.
Maki NG voted this post useful.
Old 11-29-19, 07:23 AM
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Thanks GUYs!! scheduling a call right now!
Old 11-30-19, 07:12 PM
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A dirty air filter can cause a heat pump to cycle on the high pressure switch.

Be sure that your air filter is clean.
Old 12-06-19, 10:10 PM
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Houston 204 is right a clogged filter can seriously affect the cycling and cause short cycling of a heat pump. But if the filters are clean and the problem persists your system needs to be checked by a professional. Keeping the system on in this condition can damage the heat pump motor.

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