In winter, some snow and frost on your heat pump is normal and perfectly fine. The heat pump has a defrosting cycle to keep it from freezing. But too much snow and ice can cause problems — blocked vents, broken fan blades and refrigerant leaks. This can lead to heat pump inefficiency and higher energy bills. It can also damage your heat pump. If the ice on your heat pump does not melt in the defrosting cycle, you might need to call a HVAC specialist.
Learn how to prevent ice buildup and heat pump breakdown in the winter.
Is your defroster working?
When the heat pump generates heat, the refrigerant turns to gas and then condenses along the outer coil, often freezing in the winter. Typically, your heat pump defroster will kick on to melt the ice — usually about every 15 minutes. The defrost cycle kicks in automatically in cycles when temperatures drop to a certain level. As long as the condensing fan can pull air into the unit, there is nothing to worry about.
When ice build up becomes a problem for your heat pump
If your heat pump defroster does not kick on or is not defrosting quick enough, the unit could be damaged. When ice completely covers the coils, the heat pump cannot circulate air properly, which can prevent the heat pump from heating your home.
You’ll notice signs of a problem if the entire heat pump is encased in ice and snow.
Continuing to run the heat pump when the coils are blocked can cause serious damage. Severe ice can damage fan blades, the outdoor coils and other components. It can also lead to refrigerant leaks.
Periodically check the outside of your heat pump during cold weather. If it is blocked by snow or ice and the defroster does not come for more than three hours, contact a HVAC specialist.
Why your heat pump might not be defrosting
Ice buildup on your heat pump is a sign your heat pump is not defrosting properly, and likely due to a bigger problem. You may have low refrigerant levels. The heat pump may have a faulty thermostat, temperature sensor or refrigerant metering device that needs to be replaced. You may have a malfunctioning blower motor. The reversing valve may be stuck.
If you have any of these problems, you will need to contact a trusted, professional HVAC technician.
Make sure your heat pump is elevated for proper drainage
There are drain holes stamped into the bottom of every heat pump. Make sure the heat pump unit is lifted off the ground to allow drainage. Sometimes the heat pump can become sunken into the ground, blocking the holes. Make sure the heat pump is on risers and the holes are free of grass, mud and debris.
If your heat pump does need to be elevated, this is a job best left to a HVAC specialist. Do not attempt to adjust the unit yourself.
How to avoid ice and snow buildup
Unlike air conditioners, you never want to cover a heat pump as this can disrupt air flow. You can, however, create a free standing shelter over the outside unit. Always maintain at least 2 feet of clearance from the top of the unit. This has the added benefit of cooling the unit during the summer.
You can also create a wind barrier around the unit, but be sure to leave at least 2 feet of space around the vents.
Make sure the outdoor unit is not located by an overhanging gutter or other leaking water source. Clear ice and snow away from the unit as much as possible.
What to do if heat pump defroster does not turn on
If your heat pump defroster does not turn on, check the filter and replace if necessary. This will improve airflow. Inspect the fins of the condenser fan, clearing away leaves and debris if necessary. Turn on the fan manually. If it does not turn on, there may be a problem with the blower motor. You’ll need to contact a HVAC tech.
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