The heat pump technology is the same of air conditioners. Heat pump problems and failures are those of air conditioners.
Be aware, anyway. The performance of heat pumps may fall short of the expected, due to poor installation, maintenance and sizing.
Though basic heat pump service is a DIY task, heat pumps need to be professionally serviced, especially central heat pumps. Have a competent technician to service your heat pump every 2 or 3 years. That’s important for energy-performance, and to prevent problems.
Checking the airflow of a heat pump is not as easy as checking that of a furnace, and requires special instruments (HAVC technicians use anemometers or pilot tubes).
Heat pumps require a proper air-flow, often estimated at 375 to 425 cfm per ton of heating capacity. Heat pumps are very sensitive to low-airflow.
They need to move a much larger volume of air than furnaces, and many installers (used to working with furnaces) do not take it into consideration by sizing the ducts accordingly, leading to structural low-airflow problems that are difficult to solve.
Obviously, there are other factors – besides structural ones – that can also interfere with the airflow, and that are easier to solve: dirty filters, blocked air filters...
Refrigerant charge Problems
Heat pumps are also very sensitive to refrigerant charge, and many systems – even when serviced regularly - are wrongly charged. Once again, many technicians are not knowledgeable enough, and are not able to correctly diagnose and solve refrigerant charging problems.
Dirty filters and coils
Blocked filters can cause the unit to shut down for lack of proper airflow. Filters should be changed regularly, typically monthly during the heating season.
Also do not forget to keep the outdoor coil free of snow and debris.
A good and well installed heat pump model has an outdoor sound rating of 7.6 bels or lower... You can reduce noise by mounting the fan and the compressor unit on a noise-absorbing base. The outdoor unit should be located away from windows and obstructions.
problems caused by Wind and Snow
Pay attention to the location of the heat pump outdoor unit. It should be protected from high winds and snow; to avoid frosting problems, consider protecting the outdoor unit by using bushes or fences.
In cold climates, consider mounting the outdoor compressor unit at least 2 feet above the ground; you may protect it by using a cover or a roof (without restricting airflow). It's very important to keep the snow and cold winds off and away, as much as possible.
- Check all return air grilles to make sure they aren't blocked (by furniture, for instance).
- Check all supply air grilles and make sure they are open and blowing air.
- Check the thermostat settings.
- Check the circuit breakers at the heat pump electrical panel to make sure they are "On"; check other switches, to be sure that they are also in the "On" position.