Heat Pump Problems: Troubleshooting

Heat pumps are efficient and effective systems for heating and cooling homes in areas with milder climates. But when your heat pump isn't working properly, it can be very frustrating. You can always call in an HVAC professional for help, but often you can do a little troubleshooting to see if you can find the problem yourself first. Our guide to troubleshooting common heat pump problems will give you a good place to start when something is wrong with your heat pump system.

Heat Pump Is Not Heating or Cooling Correctly

One of the most common heat pump problems is that it seems like the heat pump is not cooling or heating the home properly. Several factors can cause this issue. Fortunately, you can do some simple HVAC troubleshooting to try to diagnose what's going wrong.

  • Check the thermostat: This may seem like an overly basic step, but start with your thermostat. Make sure the thermostat is set to the right setting for the season and temperature you want — warm if you want to heat the home, and cool if you want to use the air conditioner. You should also set the thermostat within 2 degrees of the actual room temperature reading. If this is all correct, move on to the next step.
  • Ensure the unit is running: Head outside and check the outdoor heat pump unit. If it's running properly, you can move on to the next step. However, if it is not running, there could be a problem with the thermostat, the wiring between the thermostat and the outdoor unit, a power issue or a larger problem with the heat pump unit itself.
  • Check your vents: The next step is to check for proper airflow through your vents. You'll want to make sure your indoor vents aren't clogged or blocked by furniture or other household items so you have clear airflow throughout the house. Put a hand in front of the vent and see if you can feel any air coming through. If there's no airflow, the problem could be with the air handler. If you feel some air or air that doesn't feel like the right temperature, check your filters. Clean or change them if necessary. Other problems could be with the refrigerant or coils. Check with an HVAC professional for help with these issues.

Heat Pump Fan Is Not Spinning

A heat pump fan that isn't spinning could indicate a number of heat pump problems. Here's how to troubleshoot:

  • The heat pump is running, but the fan isn't: In this case, you may have a burned out capacitor or a broken fan motor, both of which should be repaired by an HVAC professional. But before you call for help, check around the unit for any debris that may be blocking the fan. Sometimes a stick can fall into the unit, or a critter may have moved in and built a nest. Be sure to turn off the power and then remove the top of the cabinet to check for debris. Don't run the heat pump if the fan is dead, as this can ruin the whole unit and cause a much more expensive repair.
  • The fan is sticking or slowing: This may mean that the fan motor is getting old and might need a replacement, but you may be able to get it going again. You can use a stick to give the fan blades a little push and see if it starts up again. Make sure you never stick your fingers in the way of the fan blades! If you can't get the fan going, it may need a capacitor or new motor. Note that you may have a two-speed or variable-speed fan, but if you're unsure, you can always check with an HVAC technician.
  • The heat pump and fan are both not working: If nothing in the system is working, check your thermostat first to see if it's on the right settings. Next, make sure the unit is receiving power by checking for blown fuses or tripped circuit breakers. If the power is working, it may be a problem with the compressor and likely needs professional repairs.

Heat Pump Is Frozen

A little bit of ice or frost on the outside of your heat pump unit is totally normal and isn't necessarily cause for concern. When this happens, the unit will usually switch to a defrost mode to reduce the frosty buildup while the auxiliary unit continues to warm the house. However, if you notice too much icy buildup or the heat pump is freezing up and not functioning properly, there may be a different problem.

If your heat pump problems are ice-related, it could be because of any of these issues:

  • Too-low levels of refrigerant
  • Defrost controls not working
  • Defrost sensors or thermostats malfunctioning
  • Sticking reversing valve
  • Fan motors damaged or malfunctioning
  • The unit needs to be leveled or elevated

When you notice too much frost or ice on your heat pump unit, try these troubleshooting tips before calling in the pros:

  • Check for clogs, debris, or dirty air filters.
  • Check for blocked or covered air vents.
  • Make sure the outdoor coil is clear of leaves, grass, snow or any other debris.
  • Check your gutters to make sure they are not clogged or overflowing and pouring water onto the unit.

Heat Pump Continues to Run After Reaching Set Temp

When your heat pump continues to run after reaching the set temp, it means something might be wrong with your system. Additionally, your home may not have the desired comfortable temperature, and your energy costs may be rising. If your heat pump runs constantly in cold weather or other situations, or your thermostat is not reaching set temperature, there are a few steps you can follow to try and solve the issue:

  • Check your blower motor: You'll want to know if it's just the blower motor that's running too much or if the whole heating system is running. Place your hand in front of the vent to see if the air coming out is warm or cold. If the air feels cold, it's just the blower that's running. If the air feels warm, the whole heat pump is running, and the blower is not the issue.
  • Check your thermostat: If it is set to "on," try setting it to "auto" and see if that solves the problem. Check the batteries in your thermostat, and replace them if they are dead or running low on power. You can also remove the thermostat unit from the wall and check for issues like frayed or disconnected wires. You can purchase a new thermostat affordably if yours is old or broken and install it easily.

Heat Pump Keeps Tripping Breaker

Do your heat pump problems have to do with a continually tripping breaker? That can be incredibly frustrating.

First, it's important to note that if your split system heat pump is installed correctly, it should have two separate breakers — one dedicated to the air handler and a separate breaker for the condensing unit. So, you'll want to check which breaker is tripping. This will give you better information about which part of the heat pump system may be malfunctioning. When you look to see which breaker is tripping, remember that breakers are often not labeled or are mislabeled.

Often, a breaker keeps tripping due to a dead short, which can be in the wiring or the motor. A bad breaker could be to blame as well, but this is less common. If the breaker continues to trip, simply resetting it will not solve the issue. Bring in a trained professional to diagnose and fix the problem.

Other issues that can trip breakers include a power supply issue, such as a brownout or severe storm. If this is the issue, you can call the power company for assistance. Another common cause involves improper maintenance of the heat pump system. To keep it operating smoothly, you should perform regular cleanings and maintenance. If clogs or dirt and dust buildup in the system, such as on the air filters and condenser coils, the heat pump may operate with higher amp draws. The extra power usage means higher power bills and a higher likelihood of tripping breakers. Be sure to clean and change filters as recommended, and perform regular maintenance checks on your heat pump system.

Heat Pump Cycles Incorrectly

A heat pump that's cycling incorrectly, or turning on and off inappropriately or too frequently, can be very frustrating. This issue may signal that your heat pump unit is overheating. If this is the case, simply checking for clogs or dirty filters could solve the issue. You should check the air filters to make sure they are clean and change them if necessary.

Another possible source of problems when the heat pump isn't cycling correctly is the thermostat. If your heat pump thermostat isn't installed correctly or hasn't been calibrated properly, it can cause a system that cycles on and off too frequently. It may not be in a good location, where it can read a proper sampling of the room's air temperature. However, if your thermostat isn't new and has been in the same location for a while without any problems before, this isn't the issue.

An HVAC technician knowledgeable in heat pump systems can find the problem causing the incorrect heat pump cycles and get your system back on track.

Heat Pump Makes Noises

Strange noises can be annoying and disconcerting. They can also be an indicator of serious heat pump problems. Noisy heat pump problems are more common in the winter months, but you still may wonder if the noises coming from your system are normal. If you're trying to diagnose a problem, it's important to know the difference between normal heat pump noises and ones that can be troublesome.

Noises You (Probably) Don't Have to Worry About

  • Louder-than-usual noises coming from the heat pump: If you hear a swooshing noise followed by other noises that are louder than what you usually hear, the system is likely going into defrost mode, and the noises are coming from the compressor. This function of the heat pump is used to clear away frost and ice buildup and is totally normal, even if a little louder than you expected.
  • Louder noises when the system starts up or shuts off: Heat pump systems naturally make some unique noises when starting up or shutting down. You might hear clicking, tapping or even louder rickety, bouncy noises at these times. Most of this noise is completely normal. But if you're attuned to the noises your heat pump normally makes, and you suddenly notice louder or different noises, it can signal a problem somewhere in the system.

Noises You Should Worry About

  • Metal-on-metal noises: If you notice something that sounds like metal scraping on other metal, something may be amiss in the system. These noises could mean that something else has gotten into the unit, such as a large chunk of ice, or the fan blades are misshapen or malfunctioning. If you hear this type of noise, turn off the unit as soon as possible. Continuing to let it run could damage the fan blades or other components inside the unit and lead to a more expensive repair. Check for debris and damage, and call for professional assistance.
  • Rattling or vibrating noises: These types of noises could be caused by several issues. It may simply be that the unit is not completely level, and elevating or leveling the unit and adding some rubber pads under the corners solves the issue. You can also check screws in the unit to ensure everything is tightly assembled and screwed in. If these efforts don't solve the noise, there may be loose parts in the ductwork or air handler.
  • Buzzing or grinding noises: These types of noises generally come from internal components like contactors and coils. Additionally, you may hear gurgling sounds from the refrigerant in the system. Some people even describe a "shrieking" noise coming from their heat pump, and this could be due to dirty motor components or a fan motor that's getting old and worn out.

No matter what type of noise you've noticed coming from your heat pump, if they are new, especially loud or otherwise worrisome, it's best to get the opinion of a heat pump repair professional.

Get Free Tech Support for your Heat Pump Problems From Us!

If you're having heat pump problems and need a little expert advice, the technicians at Ingram's Water & Air can help. Every product purchased at Ingram's comes with lifetime product support from our expert technicians. You can call us at 1-270-575-9595 six days a week and talk one-on-one with an HVAC expert. We can help you with installation questions, everyday HVAC use and troubleshooting any issues that come up. Give us a call today and get your heat pump back on track.

1 comment (view/add)
  • Jeff Fleisher
    Jeff Fleisher
    Posted on 1/14/2021

    This is okay information. It would be helpful to have a better explanation of the error codes that you see in the heat pump when things go south. I've had P5 errors but there is no explanation as to what to do next. An HVAC tech told me that Mr Cool's error code are different than any other manufacturer. I did research and that's true for all manufacturers. They have different meanings for the same codes!!! I got a Lc error after many times getting the P5 error and my brand new heat pump had to be replace. How about posting information regarding a better explanation of error code, troubleshooting them, and resolving them.


* All fields required.

Your email address will not be published. Comments will display after being approved by our moderators. Comments may be edited for clarity.