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Heat Pump Troubleshooting & Repair


Expert advice on how to fix heat pump problems, such as heating or cooling poorly and more.

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Heat pump failures are often caused by thermostat malfunctions. To test your thermostat and fix any problems, see Thermostat Repairs. If your home is heated by a furnace instead of a heat pump, please see Furnace Troubleshooting & Repairs.

If your heat pump does not heat or cool properly, freezes up, or cycles off and on too frequently, this article can help. Following are some typical problems that heat pumps can have, along with step-by-step advice for troubleshooting them and making the appropriate fixes.

If your heat pump needs to be restarted at low temperatures, check your owner’s manual. For models with a system selector switch, turn the switch to Emergency Heat and wait six hours. Then return the switch to the normal setting.

If the heat doesn’t come on even when the thermostat is set above room temperature, the problem is usually a lack of power caused by a tripped circuit breaker or blown fuse.

In this article, we’ll show you how to deal with heat pump power problems; freezing up; improper heating, cooling, and cycling; blower issues; noises; and more. If these simple steps don’t work, have a heat pump repair technician check out your system.

Note: If the weather is particularly cold and your heat pump doesn’t seem to be working right, please see Heat Pump Cold Weather Problems.

Heat Pump Doesn’t Run

If your heat pump doesn’t go on at all, there is a problem with the thermostat or the unit receiving power. Do the following:

1Be sure the thermostat is set to the proper setting (Heat if you’re calling for heat and the temperature you want the room to be). If the thermostat was replaced recently, the new thermostat may either be the wrong type (it must be made for heat pumps) or it may have been wired improperly. A mistakenly wired thermostat can fry electronic components, preventing the heat pump from working properly.


Turn the circuit breaker all the way off and then flip it back to ON.

2Be sure the heat pump is receiving power. The two circuit breakers that protect the electrical circuits providing power to the air handler and heat pump condenser may have tripped. Check both the main electrical panel and any subpanels that supply power to the unit. If either circuit breaker has tripped, reset it by flipping it to OFF and then to ON. If the circuit breaker trips again, there is probably a short in the electrical system providing power to the furnace. Call an electrical contractor.

3If the heat pump is connected to a power switch, either on the wall near the unit or inside the air handler cabinet, be sure it is turned on (many don’t have switches). If it is turned off, turn it on and wait a few minutes for the air handler to engage.

4If your heat pump has electrical elements that provide supplemental heat (most do), the circuit breakers or fuses that protect the heating elements, which are usually located in the air handler cabinet, may have tripped or blown.

HomeTips Pro Tip: Opening up the cabinet of a heat pump and working with electrical parts can be dangerous for the inexperienced. If you don’t have the necessary knowledge and skills, call a heating repair technician.

Doesn’t Heat or Cool Correctly

Heat pumps don’t discharge air that is as hot as the air discharged by oil or gas forced-air furnaces, so don’t expect their output to feel like that of a furnace. But if you’re used to a certain temperature of air and your heat pump is producing much cooler air, take the following steps. (Note that a heat pump may go into a defrost mode to prevent icing up. When this happens, it can temporarily output cold air. Also be aware that the heat pump will have to work harder to produce heat.

1Be sure the thermostat is set properly. Raise the set temperature 5 degrees F. and then wait a few minutes.


2Be sure the room-heating registers are open.


©Don Vandervort, HomeTips

Change all filters that serve the heat pump at least twice a year.

3Check the heat pump filter. If it is dirty, change it as described in the article How to Replace a Heat Pump Filter.

4Be sure the auxiliary heating elements are working (if your heat pump has these).

5Clean the coils of the outdoor condensing unit (see Central Air Conditioner Repairs).

6If these simple steps don’t work, have a heat pump repair technician check out your system—either the blower isn’t working properly or the system is out of balance in some other way. For example, the reversing valve may be stuck in the wrong position.

Freezes Up or Trips Breaker

It isn’t unusual for a heat pump to ice-up in really cold weather, but it’s defrost cycle should kick on periodically to melt the ice. If the condenser unit of the heat pump is frozen up and the defrost cycle doesn’t melt the ice, turn it off. Make sure none of the return-air registers are blocked, and check the filter to make sure it isn’t clogged. If there doesn’t seem to be a problem with air flow to the unit, see more information at Heat Pump Cold Weather Problems or call an HVAC service professional.

If the power to the heat pump goes out, be aware that most heat pumps have auxiliary heating elements that provide heat when the weather gets really cold and the heat pump’s efficiency drops too low. These elements automatically turn on at a fairly low temperature—around 20 degrees F. When they come on, they may be drawing too much power, which can trip the circuit breaker. Just locate the circuit breaker that serves the heat pump and reset it.

Heat Pump Blower Doesn’t Work

This may be caused by one of two things: the thermostat mounted on the wall or the limit switch located on the heat pump just below the plenum (the box that distributes heated air to all of the ducts). The limit switch in a furnace or heat pump is designed to shut off the heat pump if the air in the plenum gets too hot.

Check the thermostat to see if the Fan switch has been turned on. If it has, turn it to OFF or to Auto. If it is set to OFF or Auto already, the heat pump’s limit switch needs to be adjusted. Call a heat pump repair technician to make the adjustment or, if you are handy with this type of repair, follow the instructions in your owner’s manual to reset the pointers on the fan side of the limit control. The lower pointer should be set to about 90 degrees F. and the upper one should be at about 115 degrees F.

If the motor runs but the blower doesn’t move air, the belt that connects the two probably has broken. Replacing it is an easy fix:

HomeTips Pro Tip: Opening up the cabinet of a heat pump and working with electrical parts can be dangerous for the inexperienced. If you don’t have the necessary knowledge and skills, call a heating repair technician.

1Turn off all power to the unit. Remove the door on the front of the air-handler cabinet to give you access to the blower (it may be on a slide-out drawer.) Check the number stamped on the belt and get an exact replacement from a home improvement center or heating supply outlet.


2Slip the belt on the motor’s (smaller) pulley first and then start it on the blower pulley, as shown at right. Rotate the blower pulley by hand, holding the belt in place but taking care to keep your fingers from getting caught between the belt and the pulley. The belt should slip right into place.

3If the belt seems too tight or difficult to put on using this method, it may be necessary to adjust the motor mount to provide more slack. Then just re-tighten the tension once the belt is in place. Check the manufacturer’s specifications for proper tension—in most cases, the belt should deflect about an inch when you press down on it.

Heat Pump Cycles Incorrectly

When a heat pump turns off and on too frequently, the problem may be that the unit is overheating because of a clogged filter or blower that is malfunctioning. Try cleaning or replacing the filter.

Check the thermostat if your heat pump is cycling poorly.© Mariusz Blach |

Check the thermostat if your heat pump is cycling poorly.

Then check the thermostat, which is more likely the cause. It usually means that the thermostat is improperly calibrated or that it is installed where it doesn’t sense a proper sampling of room air. If the thermostat has been located there for a long time and the heat pump has worked fine before, the latter case is not the issue.

When room temperature rises higher or drops lower than the set temperature on the thermostat, the problem is usually the heat anticipator in the thermostat. See Thermostat Repairs.

If that doesn’t do the trick, call a heat pump repair technician.

Heat Pump Makes Noises

Squealing sounds and grinding noises are not good. Shut off the unit and call a heat pump repair technician—the motor’s bearings are probably shot.

If the heat pump makes rattling noises when it runs, be sure the cover panels are screwed on tight. If they aren’t, tighten them. Other noises may be coming from rattling ductwork or loose parts in the air handler.

Many heating ducts are metal, so they conduct noise quite readily from the air-handling unit to your rooms. To break the conduction of sound, you can have a heating contractor insert flexible insulation ductwork between the heat pump and the ductwork runs.

If you hear a pinging or popping sound coming from the ductwork, this may be caused by thermal expansion or by air blowing past a loose flap of metal. Track along the duct runs, listening for the sound. If you find it, make a small dent in the sheet metal to provide a more rigid surface that’s less likely to move as it heats and cools.

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Join the Conversation

  • robert miske

    condenser freezes inside furnace, also only about 60% is cold. the line coming from heat pump is iced over at the pump.

  • Don

    Robert, change or clean the filters and make sure nothing is restricting air flow. See Turn off the unit long enough for the ice to melt. If this doesn’t work, call an AC repair person because you may have a refrigerant leak or a problem with the blower.

  • Joe Brummett

    i have recently installed a new heat pump and thermostat. however, it keeps burning out a 5amp fuse located in the bottom of the furnace. what do i need to look for to fix this problem. thank you

  • Billy

    The fan outside on the heat pump runs when the heat is on.I thought the fan only ran when the air conditioner was on Also the unit is noisy. It is a new Heil Heat Pump

    • Ann Korn

      No, ours makes a lot of humming noise without fan running. I think it is when the air conditioner is taking humidity out of the air. It can be very noisy. Then the fan kicks in.

  • Clay

    When the heat cuts off the unit outside makes a loud exhausting sound like it’s releasing pressure. Is that normal? Also when the outside unit stops running with the fan on it will turn back on almost immediately without the fan. Is this also normal?

  • amanda

    my heat pump or thermostat is not working properly. we set the heat on 69 and the next morning it was 80. we bought a new thermostat but it is doing the same thing. what could the problem be?

  • Jim Phipps

    My heat pump isn’t cycling correctly. We have the temp set to 75 and it’s reading 65 and dropping. I can cycle over to AC cooling and then back to heat and then the system starts blowing warm air after about 2 minutes. It will continue to run for about 15 minutes and then shut off, wether it has reached it goal temp of 75 or not. Any ideas on what the cause would be?

  • Donna Freeman Hood

    My heat pump blows cold air. They said the switch was bad. Can you just replace the switch

  • brad

    every day or two, the blower stops blowing air into the house. i have to shut the unit off, switch the fan to “on” so it will start blowing air again and then turn back on heat or cool.

  • Alanna McMullan

    We have a 2400 sq foot home that we purchased 3 months ago. The house has 3 electric heat pumps. Our electric bill came in around $330 with all three heat pumps set to 70 degrees. We quickly decided to install a pellet stove to reduce the cost of electric heat. Once the pellet stove was installed we set 2 of 3 thermostats to 64 degrees so they would not turn on as the pellet stove was keeping those 2 zones at 70 degrees. The third heat pump is to the lowest level of the home and we need it to supplement the area that the pellet stove did not heat. Our next month’s electric bill jumped to $550. We were baffled as we were now only using one heat pump and running a 4 amp 120 v pellet stove. We had an electrician come out and had everything check out fine with the entire electrical system, we had the electric company come and check the meter and usage and found nothing abnormal, and all three heat pumps were checked out to be running in mint condition. So with no answers, we turned two of the three heat pumps off entirely and our electric use for the day decreased from about 200 kWh to 120 kWh. (outside temp was similar to the day before we turned them off) Any feedback on why they are using electric when the temp on them is set well below the room temp ?

    • Don Vandervort, HomeTips

      I suspect the issue is extremely cold outdoor temperatures, since much of the US is dealing with that problem. When outdoor temperatures drop really low, the heat pump doesn’t use refrigeration technology to create heat—it users electric coils, which take a lot of power. Please see:

  • Kenneth Johnson

    I have a Goodman heat pump, it give heat only in the emergency heat mode. Are there any suggestion to the problem.

  • Don Vandervort, HomeTips

    It sounds like the heat anticipator setting in the thermostat needs to be adjusted. See

  • Pat McBride

    If it’s under the set outside cold temp, the heat pump part of the system will not run. It goes into emergency heat mode and uses electric elements.

  • James Tomlin

    Hey i have a heat pump that stays runninng it will not kick off what should i do

    • brandi cooper

      Same here. Did you get a resolution to this issue?

  • chris

    Handler blower motor was bad. Replaced and fan worked but noticed only warm air momentarily then blowing cold air continuosly. Also outside compressor fan doesnt seem to be working. I also replaced capacitor. Any suggestions would be appreciated. Same digital thermostat.

  • …our blower shut down last night and I found online directions to replace it should it be the issue… …yet, after speaking with friends in the know, I threw both furnace and outdoor compressor breakers… …the blower sprang back to life but still has what sounds like a far off train hum – is this something that should concern me..?

  • Libby Carmack

    My heat pump is about 20 years old. It’s a York. The system stopped blowing cold air and the service tech put on a new blower motor,blades and a blade hood. Charged me $400.Added freon worked about 6 hrs then stopped blowing cold air. Came back next an and added more freon. Worked6 hrs then stopped again . Says likely compressor. Offered to replace compressor $3400. What do you think?

    • Brian Houting

      depends on where you live. The compressor you can go on line and get them from 200 dollars on up . Then ask them how much they would charge if you buy the compressor
      but it sounds like you have a leak in the line some where if you need to keep putting freon in it. That sounds like a lot of money I would see how much a new one would cost first.

  • alfredo_tomato

    No cooling, no condensation that points to a leak. Outside unit seems to work. The thumping sound we hear when the ac is turned off doesn’t happen. I have a feeling it is the blower motor. It’s too darn hot and muggy. Am I right that it could be the motor?

  • Mark

    I have a 2010 Carrier Heat Pump Model FX4DNF019, and recently the blower stopped working altogether. When the blower failed, I smelled something like an electric motor burnout. The fan(?) makes a humming sound when powered up and sounds as if it is struggling to turn. I cycled the power no changes, air filter was replaced in previous 30 days, could it be a controller, or might it be the motor?

  • Diane

    My heat pump has a short circuit. Can this be fixed or do I have to get a whole new heat pump?

  • David Franklin

    I have to spin the fan by hand to get to operate, this is every time it shuts off

  • Jose Sosa

    My blower doesn’t seem to be turning fast enough. Could the motor be skipping. Turning very freely not out of bala
    nce. Turning slower than normal.

  • Jim Manson

    fixed orifice heat pump shows near perfect operating pressures and cycles properly in cooling mode but trips high pressure switch when trying to heat.

  • clair

    after a heat pump heats a room does it blow cool air.We have a Mitsubishi Mr.Slim

    • Jad

      I believe it is the fan, make sure to so switch the fan to auto instead of on. This should solve ur issue.

  • Clinton Adee

    I have a tempstar heat pump. The blower doesn’t always work properly when using heat. When it does work it blows warm air but not as warm as it should be. Sometimes the blower stops working but the pump is still working and making a loud buzzing noise. What could this problem be?

  • Sarah Spence

    New unit put in the month of July. Set unit to heat last week and noticed the outside unit constantly running. Looked at the thermostat and it had switched to auxiliary heat. Turned unit to off wired about 30 minutes. Turned back on heat. It ran a few minutes then shut off but came right back on in auxiliary heat.

  • Shonna Monroe Brooks

    My heat pump stopped working this morning, it was running/working fine last night. We have flipped all breakers and made sure the thermostat was set right. I also flipped it from auto to on just to see if the fan would come on but nothing inside or outside. What could the problem be?

  • disqus_Gz7SQt6Y7G

    my thermostat is set on ac, the ac was working fine, it stopped and when it restarted the heat came on, the thermostat was still set to ac, the heat lights (green and red lights) came on also? help

  • Jeff Jackie

    My heat pump blows warm air for a while and then blows cold air. When it’s blowing warm air it comes out at about 85 degrees. That’s great. But after a while, it starts blowing cold air that I’ve measured at about 62 degrees at the registers. I assume the heat pump is working since it does blow warm air but why does it cycle to blowing cold air. On a really cold day, my house will not heat to above 62 degrees, even with the thermostat set at 74. As an aside, if I switch the thermostat to OFF and leave it off for a while and then switch it back HEAT, it starts blowing warm air for a while.

    • Nathan Coleman

      Mine is doing the same thing. What did you find?

  • dennis

    power outage the other night blew the control few ..replaced it and it and it keeps blowing on ramp up…and ideas ? goodman 4 ton ducted heat pump

  • Don Vandervort, HomeTips
  • James Siegfried

    I replaced the thermostat last year. The other day I was out near my heat pump and I heard what sounds like a transformer hum coming from it, but the unit was off(inside and outside). Everything works fine. Did I wire the thermostat incorrectly?

  • keith wehner

    I have a Lennox 1988 2 speed heat pump and the outside fan doesn’t run in low speed anymore. Is this a wiring or thermostat issue?

  • Diane Myles

    i turn my heat pump down to 62 and we go out and come back home and its running and it is 17 degrees outside and my power bill is high WHY DOES THAT HAPPEN

  • Phil Agur

    I had the bearings fail in my condenser fan motor and replaced the original 3 speed (only used 2 of the winding) with a single speed. Now when I turn the heat pump on the Nest thermostat can control when the compressor runs but the condenser fan never turns off. The nest changes display color when it’s asking for cooling. I’ve set it up to 90 and the heat pumps shuts off but not the inside fan. We’re glad to have the heat pump working in our heat wave but I think I need to get the fan only running as required not FT.

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