A frozen heat pump can be an alarming sight. The good news is that it’s often a normal part of your unit’s operation. There are a few instances, however, where a frozen heat pump might indicate a problem with your system. In this post, we discuss reasons why your heat pump might freeze over at times when it shouldn’t, and how to prevent this from happening.
How Heat Pumps Work
Your heat pump uses refrigerant to absorb heat from the air outside and transfer it indoors. This might seem odd in the winter, but there is actually plenty of heat for refrigerant to absorb as long as temperatures remain above freezing. As heat is transferred to the refrigerant, excess moisture from the air tends to build up on your outdoor unit’s coils. When it’s cold enough outside, this excess moisture can freeze on your heat pump, impeding the system’s performance.
Luckily, heat pumps are designed to handle these instances. Once the unit detects a significant build-up of ice, a defrost cycle is activated, reversing the heat pump to temporarily operate in cooling mode. This allows heat from the refrigerant to melt the ice while a backup heating cycle runs to keep your home warm.
When Should You be Concerned About a Frozen Heat Pump?
If your heat pump remains frozen after roughly 30 minutes of running the defrost cycle, it could indicate a problem. In some cases, the defrost cycle might never kick on, allowing additional layers of ice to build up. Let’s look at common reasons for a heat pump that won’t defrost:
- Faulty thermostats/sensors.
- Low refrigerant levels.
- Improper airflow around the unit.
- Broken outdoor fan motors.
- Faulty defrost controls.
- Dirty filters.
How to Prevent a Frozen Heat Pump
Keeping up with the following winter maintenance can help prevent problems:
- Clean/replace filters regularly, roughly once a month.
- Clear away snow/debris around your unit to ensure room for proper airflow.
- Use a garden hose to melt away any ice build-up on top of your unit.
Work with a Professional!
If you continue to have problems with a frozen heat pump, have a professional HVAC technician take a look! Regular inspections and tune-ups go a long way toward preventing problems right when you need your unit most.