Heat Pump Outside Unit Not Running

A heat pump from any brand mostly has the same system which is providing cooling during warm weather such as summer and heating during colder weather. A heat pump usually could last around 12 to 22 years depending on the brand, quality of the unit and the installation project.

However, you will meet technical problems several times which is common. You could contact a local technician to help you to fix the problems. It is recommended that you call the same contractors who installed a heat pump or a qualified technician who knows the system.

If you can diagnose and repair by yourself common problems of your heat pump, it will save time and costs when there are problems. Several factors could make your heat pump outside not running such as problems with power, thermostat, a heat pump is defrosting when it is in a heating mode or the thermostat suddenly changes into emergency heat mode.

Power Related Problems

One of the common problems of a heat pump that stop running is related to power. Check first if it could receive power. Check a power switch of the unit, it could be on the wall or even inside of the cabinet of the air handler. Check if it’s turned on. If it’s off, you can turn it on wait several minutes to have it running.

There is a possibility that there are circuit breakers or fuses have tripped or blown. The circuit breakers shield the electrical suites that provides power to condenser and air handler. You also could check the main panel that provide electrical power, if there is any trip from a circuit breaker, you could try to reset it by turning it OFF and put back it ON.

After checking the main panel, you could also check if there is any subpanel in the heat pump. Try with the same instruction as the main panel by restarting it. Reset the subpanel by switching it OFF then turn it ON again. Wait for a few minutes and then if it trips again, it could be an electrical short in the system. You may need to contact an HVAC technician to fix the issue.

There are several factors which could make the heat pump doesn’t receive the power. It could be the problem of the fuses which will be easily replaced by a contractor. However, it could be because of other problems such as bad connection, seized blower motor, issue on the wiring or a shortage in controller board.

If you can turn on the heat pump but it is off again on the short period, there could be a technical problem in its major component. You also could try to check other signs of a technical failure from your heat pump such as leaking, irregular functioning or unusual noises. Any signs will help an HVAC technician to identify and solve the issue.

The Thermostat is in Emergency Heat Mode

A thermostat is one of the most important elements in a heat pump. Make sure that thermostat is set in a proper heat. Another problem could be the thermostat is improperly wired which can prevent the heat pump to work properly.

You also need to check whether your heat pump thermostat is in emergency heat mode.

What is emergency heat?

When the temperature outside is too cold and your heat pump cannot remove heat from outside, the thermostat will use the second stage of heat which is called Emergency or Auxiliary heat. Usually, if the outdoor temperature is below 35ᵒF, it could trigger the thermostat in an emergency heat mode.

Emergency heat mode will cause the electric heating elements and refrigeration system to shut down which cause your heat pump doesn’t work properly. If you have this situation, you don’t need to be panic. You could reset the thermostat to be back in normal operation.

if you have reset the thermostat and the problem still occurs, you need to call an HVAC technician because of there probably issues which your heat pump system. An emergency heat mode is not only inefficient but also will cost you more than regular operation.


Above tips is merely a guideline for common problems happened on a heat pump. However, you will need to have an HVAC contractor to do a routine check and maintenance to avoid any technical problems. This also will help a lot for the system durability.

Please also note that it is dangerous for you to open a unit cabinet and try to work with electrical parts if you are inexperienced and don’t have essential knowledge on this matter. It is strongly recommended for you to call a qualified and experienced HVAC technician to identify the problems and fix your heat pump.