When a faulty component or simple glitch pushes your heat pump to the limit, it works up quite a sweat in the form of excess condensation on the outside coil. The condensation on the extremely cold coil begins to freeze, and may quickly snowball out of control until the coil is encased in ice.
Learn which factors contribute to ice accumulation, and you may troubleshoot the issues you feel comfortable about handling, or, as with many malfunctions, you may need to call in an HVAC professional.
Demand-defrost malfunctions allow ice to accumulate on the coil. There may be a sticky reversing valve, a bad solenoid coil, a faulty sensor, timer or relay, and/or a thermostat malfunction. Another possibility for older heat pumps is that demand-defrost is indeed activating, but it’s not defrosting long enough to melt all the ice.
- What to do: Call your HVAC pro.
Airflow issues include snow drifts, ice and/or debris preventing free airflow through the unit. If water accumulates on top of the unit from perhaps a leaky gutter, or rain and sleet, and then freezes, often the entire unit will follow suit and become encased in ice.
- What to do: Keep the area around the outside unit clear of airflow blockages in all directions by at least 2 feet. Prevent water and ice from accumulating on the top of the unit.
Incorrect refrigerant charge overworks the heat pump, inhibits proper defrosting and increases utility costs. (You can’t actually check refrigerant charge yourself to determine if this is the issue. Your HVAC pro will check this during a preventive maintenance visit.
- What to do: Call your HVAC pro for service.
You may try melting the ice-encased coil by spraying it with a garden hose. If you’re able to melt the ice, but ice accumulates again once the heat pump is running, call your HVAC pro. Do not use any tools in an attempt to chip the ice away, or you may seriously damage the heat pump.
Our goal is to help educate our customers in Hamel, Illinois and surrounding areas about energy and home comfort issues (specific to HVAC systems). For more information about frozen heat pumps and other HVAC topics, download our free Home Comfort Resource guide.
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