In North America, heat pumps are a popular choice for heating and cooling homes. A heat pump is an electrical device that extracts heat energy from a particular source and transfers it to another area, offering an energy-efficient alternative to furnaces and air conditioners. However, internal errors can also cause the equipment to run inefficiently. A common example is a unit turning on and off too frequently, a phenomenon known as short cycling. In this article, Acker Heating & Cooling, a reputable residential and commercial HVAC contractor in Georgia, discusses how heat pump systems operate and the possible reasons why your heat pump is shutting off prematurely.
How Do Heat Pumps Work?
A heat pump transfers heat by circulating a fluid substance called refrigerant through a cycle of evaporation and condensation. The compressor pumps the refrigerant between two heat exchanger coils. In one coil, the substance is evaporated at low pressure and soaks up heat from its environment. Then, it’s compressed during transport to the other coil, where it condenses at high pressure. At this point, it releases the heat that was absorbed at the beginning of the cycle.
The heat pump cycle is fully reversible. Heat pumps can provide year-round climate control for your living space — supplying heating during the cold, frosty winter months and cooling and dehumidifying throughout the summer season. Moreover, since the ground and air outside contain a good amount of heat at all times, a heat pump can supply heat to homes even on ice-cold winter days. In fact, air at –0.4°F contains about 85 percent of the heat it contains at 69.8°F.
Reasons Your Heat Pump Keeps Shutting Off
If your heat pump is pushing out heat or cool air that’s not in sync with the temperature setting on the thermostat, short cycling may be to blame. Here are four common issues that often result in a heat pump shutting off and restarting several times throughout the day.
Inaccurate thermostat measurements. Sometimes, a heat pump unit experiencing short cycling can be caused by a thermostat gauging the temperature in an inaccurate manner. This forces the heat pump to turn off in the middle of heating or cooling before the desired temperature is reached. Fortunately, this dilemma can easily be fixed by adjusting the thermostat’s heat anticipator, an electrical resistor component mounted in the center of older mechanical thermostats. You can perform this solution manually, but if you’re not too familiar with the device, a trained residential and commercial HVAC technician can lend you a hand.
Another possible reason is the thermostat was installed in the wrong location. In order to measure air temperature accurately, the thermostat must be placed in a specified area where sunlight won’t directly affect it and drafts and sources of outside air can’t reach it.
Incorrectly-sized heat pump. A heat pump of the incorrect size is one of the most expensive problems to fix. If your unit continually turns on and off, the reason could be because the heat pump is too powerful or too indisposed to sufficiently heat or cool the designated space. It’s important to consult with a trained technician and allow them to perform a heat load calculation in the space or room wherein the heat pump is to be installed before proceeding with the actual installation. The calculation will determine the optimal heat pump power output for the best heating and air conditioning experience.
If an amateur technician fails to make the necessary calculations or performs them incorrectly, it’s likely that an oversized heat pump will be installed in the home, compromising the efficiency of the system and the comfort of the residents. Whether you’re installing brand-new equipment or addressing some minor issues here and there, make sure that you work with qualified, trained professionals to avoid wasting your time, effort and money.
Clogged air filter. The role of an air filter is to trap airborne particulates and contaminants, such as dirt, dust and pollen, in order to clean the air that circulates through the heat pump. This prevents these particles from getting sucked into the vulnerable working parts of the system and causing an disruption. However, when air filters aren’t cleaned thoroughly at suggested service intervals, all the dirt, dust and other debris will accumulate and create clogs. This will restrict the airflow of the system, resulting in an unwanted overheating scenario. And when heat pumps overheat, it’s only a matter of time before they fail and shut down.
Not many people realize that short cycling due to overheating can cause serious long-term damage. To avoid this dilemma, make sure to inspect the air filter regularly and clean or replace it as needed. For a standard 1” filter, cooling and heating system experts recommend changing the filter at least once a month, especially when you’re using the heat pump, or even the furnace or air conditioner, on a daily basis, which is normal during extremely cold and extremely hot weather. In milder seasons, you may opt to replace the filter once every six weeks or every two to three months.
Leaking refrigerant. The air-cooling function of a heat pump is achieved through a process that relies heavily on the refrigerant. In cold weather, refrigerant absorbs heat from the outdoors, pressurizes it and then releases the conditioned air into the interior space. However, if the heat pump happens to be leaking refrigerant, there’s a good chance that the system will short cycle and fail to sufficiently heat the indoor air. One indication of a refrigerant leak to look for is ice buildup on the outdoor unit of the heat pump system. When ice buildup is evident, a trained HVAC technician should be contacted as soon as possible to fix the leak, test the repair and recharge the system with the correct amount of refrigerant fluid.
How to Maintain Your Heat Pump
Like all cooling and heating systems, proper maintenance is key to efficient heat pump operation. It’s important to have a professional technician service your heat pump at least once a year in order to prevent mild to serious problems. Some of the actions that the technician will perform include:
- inspecting the ducts, filters, blowers and indoor coils for dirt and other blockages;
- diagnosing and sealing duct leakage;
- measuring to confirm sufficient airflow;
- lubricating motors and inspecting belts for tightness and wear;
- verifying correct electrical control;
- verifying correct refrigerant charge by measurement;
- and much more.
Contact Us for Professional Heating & Cooling Services
It’s critical to make sure your heat pump is in perfect working condition to maintain good indoor air quality and optimal comfort all-year-round. If your system is experiencing some issues, Acker Heating & Cooling is more than happy to help you. From heating and air conditioning repair to equipment installation and air duct sealing, we’re experts at finding suitable long-term solutions for your unique household HVAC needs.
Call us today at (706) 989-6663 or fill out our contact form to schedule an appointment. Our experienced team is committed to providing every homeowner we work with in the greater Athens, GA, area the comfortable, efficient living space they deserve.