As a rule, it’s best to have an AC repair technician handle the troubleshooting of your heat pump if it isn’t working properly. However, it wouldn’t hurt to learn a bit about the basic anatomy of a heat pump. Having a basic understanding of how the various components work can help you assess the different quotes and estimates for heat pump repairs and do a bit of minor troubleshooting.
A Heat Pump’s Main Components
A standard heat pump has two main components: an outdoor condenser unit that transfers or removes heat from indoor air, and an indoor unit through which air flows.
Here’s a more detailed overview of the function of each component:
- Compressor – The compressor—which is located outside—is responsible for circulating refrigerant through the coils. Conventional piston compressors can be a bit noisy, so if you want to reduce the noise coming from your heat pump, you might want to install one with a scroll compressor. Since it has fewer moving components, scroll compressors produce less noise. They also last longer and can produce air that’s warmer by about 10° to 15°F when in heating mode.
- Air Handler – The air handler is installed in your home and is composed of four components: the blower, filter, evaporator and heat exchanger. As the name suggests, the blower pushes air through the air ducts while the filter removes dust and other particles. The evaporator and heat exchanger collect the heated or cooled refrigerant, which will then be used to condition the air. After that, the excess moisture that was removed from the indoor air will be diverted outside through a drainpipe.
- Thermostat – The thermostat controls the air handler and evaporator, and by extension the temperature inside your home.
Here’s a tip: If you want to reduce your electricity costs or are considering a more energy-efficient air conditioning replacement, you might want to install a programmable thermostat. Programmable thermostats can be set to automatically adjust the temperature at certain times of the day. For instance, you can set it to lower the temperature when you’re away at work and gradually increase it again later in the day so indoor temperatures have reached a comfortable level by the time you get back home.
- Thermostatic expansion valves – Thermostatic expansion valves control the intensity of the flow of refrigerant, similar to how a faucet controls the intensity of the flow of water.
- Reversing valves – Reversing valves change the flow of refrigerant to either cool or heat the interior.
- Heat strips – Heat strips are electrical components that provide extra heat on cold days.
- Control board – This component controls your heat pump’s cooling, heating and defrost modes.
How Heat Pumps Work
Heat pumps can be set to either cool indoor temperatures or provide heat. Here’s an overview of how the different components function:
In Air Conditioning Mode
The heat pump’s motorized fan draws warm air into the ducts. The compressor then begins to circulate refrigerant between the evaporator and the condensing units to cool warm air. The cooling process starts when warm air is pulled into the air handler and refrigerant passes through the coils and absorbs heat. Next the cooled and dehumidified air is pushed by the blower through air ducts and filters. The cycle is then repeated.
In Heating Mode
When you switch the heat pump into heating mode, the refrigeration process is reversed. Heat is absorbed from outdoor air by the indoor coil and is then transferred to the coolant, which is compressed to increase its temperature. Indoor air is drawn by the motorized fan into the air ducts and heat pump. Cool air passes through the hot coolant and is then distributed throughout your house.
Heat Pump Maintenance
Over time, wear and tear could cause some of the components to malfunction, which is why it’s important to have an AC repair and maintenance technician inspect your heat pump at least once a year if it’s used as a supplementary heating and cooling system and twice a year if it’s used as your main heating and cooling system.
Along with routine inspections, what other maintenance tasks should be performed? Here’s a maintenance checklist:
- Change the air filter every three months or so – As a rule, quality air filters should be replaced every 90 days. However, you may need to change them more frequently depending on how often you use the heat pump, whether you have any pets at home or if there’s anyone in the household with allergies and other respiratory conditions. If you have pets, the filter should be replaced every two months. Since cats and dogs shed their coats during the transition period between seasons, remember to replace the filter when winter turns to spring and summer turns to fall if you have pets. If, on the other hand, you have family members with respiratory conditions, the filter should be replaced every six weeks to maintain optimal indoor air quality.
- Remove any grass, leaves or dirt near the outdoor unit – We recommend maintaining a clearance area of about two feet around the outdoor unit.
- Dust the supply and return registers – Cool or warm air may not be able to circulate freely if dust is blocking the air vents.
Heat Pump Issues Caused by Infrequent Maintenance
What’s the worst that could happen if you occasionally forget to have your heat pump maintained or inspected? Some homeowners think HVAC and heat pump maintenance is an unnecessary expense, but they often fail to take into account the costly issues that could later emerge due to infrequent maintenance.
Issues you might encounter include:
- Higher cooling and heating costs – A heat pump that wasn’t maintained frequently will consume 10% to 25% more electricity than a well-maintained one.
- Poor indoor comfort and air quality – Dirty vents and fans can drastically lower indoor air quality and prevent air from being distributed evenly, creating cold or hot spots.
- Reduced lifespan – Poor airflow lowers your heat pump’s performance and may increase the strain put on components such as the compressor.
No matter how you look at it, it simply makes practical—and financial—sense to maintain your heat pump regularly.
Is It Time for a Replacement?
Of course, maintenance can only do so much. At a certain point, wear and tear will cause some of the heat pump’s components to break down. In general, HVAC and air conditioning replacement contractors recommend replacing heat pumps that are more than 10 years old.
What Are the Signs You Might Need a Heat Pump Replacement?
- Poor indoor comfort – The decreasing performance of older heat pumps may result in poor indoor comfort. If your home never feels warm or cool enough despite your heat pump running regularly, it may be time for a replacement.
- Higher utility bills – Older heat pumps are also less energy efficient than newer models.
- Frequent repairs – As your heat pump ages, it will suffer more frequent breakdowns, and will thus need repaired more often. Repairs may not cost that much individually, but they can quickly add up. That’s why it’s more cost effective to replace an aging heat pump in the long run.
- The heat pump is running constantly – Heat pumps aren’t designed to run constantly—rather, they’re designed to run in cycles. If the heat pump is running constantly, it might not have enough heating or cooling capacity to keep indoor temperatures at comfortable levels.
One more thing: Only qualified technicians should handle heat pump and AC troubleshooting system issues. That’s why it’s important to vet a contractor before hiring them.
If you’re looking for HVAC technicians near you, here’s a vetting tip: The number of years a contractor has been working in the industry should give you a good idea of their level of expertise.
Air Products & Services has been providing professional HVAC and AC troubleshooting system services to local residents since 1979. To get a free estimate on new equipment, call us at (818) 989-2030 or fill out this form. We serve homeowners in Tarzana, CA, as well as the surrounding communities.