Is your heat pump in need of repair? Here are some methods for troubleshooting common heat pump problems and making the appropriate fixes:

Heat Pump Does Not Heat
Heat pump failures are often caused by thermostat malfunctions or a tripped circuit breaker or blown fuse. If the heat doesn’t come on even when the thermostat is set above room temperature:

1) Be sure the thermostat is set to the proper setting (“Heat” if you're calling for heat, and the temperature you want the room to achieve). 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 erroneously-wired thermostat can fry electronic components, preventing the heat pump from working properly.

2) Be 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 secondary sub-panels that supply power to the unit for these circuit breakers. If either circuit breaker has tripped, reset it by flipping it all the way 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.

3) If 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 has a switch that is turned off, turn it on and wait a few minutes for the air handler to engage.

4) If 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. 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.

Heat Pump Frozen Up
If the condenser unit of the heat pump is frozen up, 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, call an HVAC service professional.

Insufficient Heat
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, the following is what to check. Note that a heat pump may go into a defrost mode to prevent icing--when this happens, it can temporarily output cold air. Also be aware that the heat pump will have to work harder to produce heat.

1) First be sure the thermostat is set properly. Try raising the set temperature 5 degrees and waiting a few minutes.

2) Be sure the room-heating registers are open.

3) Check the heat pump filter. If it’s dirty, change it.

4) Be sure the auxillary heating elements are working (if your heat pump has these). See "Heat Pump Does Not Heat," above.

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

6) If 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.

Heat Pump Trips Circuit Breaker
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 Fahrenheit. 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 Turns On and Off Too Often
If your heat pump cycles off and on too frequently, the problem is likely to be with the thermostat. See the thermostat-related problems below for information on alleviating this problem. 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. If that doesn’t do the trick, call a heat pump repair technician.

Major Room Temperature Swings
When room temperatures swing more than about 3 degrees between when the heat pump goes off and on again, it generally means that the heat pump isn’t cycling on often enough. See “Adjusting a Thermostat Heat Anticipator.”

Room Temperature Goes Too High or Too Low
When room temperature rises higher or drops lower than the set temperature on the thermostat, 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. See Heat Pump Thermostat Problems.

Blower Runs Continuously
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 must be adjusted. Call a heat pump repair technician to adjust the limit switch 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 Fahrenheit and the upper one should be at about 115 degrees Fahrenheit.

Air Handler Makes Noises
Squealing sounds 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 (see below) or loose parts in the air handler.

Air Ducts Are Noisy
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.

Heat Pump That Requires Restart at Low Temperature
If your heat pump needs to be restarted at low temperature, check your owner's manual. For models with a system selector switch, turn the switch to "Emergency Heat" and wait for 6 hours, then return the switch to the normal setting.