Why Heat Pump Freezing Up?

In fact, it is normal for your heat pump to freeze over in winter. If in fact, under certain weather conditions, it is natural that the entire coil will be lightly covered with ice, although a defrost cycle will begin when excessive ice accumulation is detected. In defrost mode, heat from the refrigerant is used to melt ice.

Sometimes your heat pump will be completely covered in ice for an extended period of time. When this happens, you'll need to have it checked by a professional technician, as this may indicate a problem with it. Our Heating and Ductless Air Conditioning team provides more insights in this post.

Why is your heat pump freezing?

1. Insufficient airflow

The temperature of the heat pump refrigerant may drop below freezing. If there is not enough airflow through the unit, moisture in the air can freeze on the evaporator or condenser coils. To prevent this from happening, remove any leaves, debris or snow that may be blocking the coil to ensure good airflow. If the coils are dirty, cleaning them can prevent freezing.

2. Cold water

When freezing rain falls on the heat pump, the rain causes the top of the unit to freeze, and the rest of the unit freezes quickly. If your heat pump won't thaw on its own after a day, or if it freezes after thawing, call an HVAC specialist for proper de-icing. Dripping water from leaking gutters is also a common cause of heat pump freezing. Check gutters and make necessary repairs.

3. Subsidence

Most heat pumps stand on concrete slabs. Over time, the slab will sink into the ground. Even an inch or two of settling can block drainage paths for ice melt and impede airflow, causing ice to build up. If you suspect this is your problem, contact an HVAC technician to have the unit leveled.

Troubleshooting Tips When Your Heat Pump Frozen

If your heat pump is covered in frost or ice, first check that the defrost cycle is on. If the ice melts after a while, your pump should run normally again. However, if it is still completely covered in frost after 30 minutes with the defrost cycle still on, you may have to shut down the system and call your heating and air conditioning contractor for a thorough inspection. Here are other troubleshooting steps you can take:

1. Check the unit's air filter to make sure it is not clogged or damaged. Replace if dirty.

Try to clear any ice on top of the heat pump. Use a garden hose to melt the ice instead of poking it with a sharp object; the latter may damage your equipment.

2. Check indoor vents and registries to make sure they are not blocked by boxes, clothing, furniture or other items.

3. Leaves, grass, twigs, snow, and other materials near the heat pump can disrupt its airflow or block the outdoor coil, so be sure to remove them properly.

If you have other problems when using the air source heat pump, please contact us. Our HVAC experts will give you the best advice.