Is Frosty the Heat Pump an Unwelcome Guest? How Can You Tell?
A frosty heat pump coil in the outside cabinet is part of normal operation in certain weather conditions. If a component of the heat pump is malfunctioning, however, ice accumulation can snowball to where the system may become damaged further with quite a chilling effect on home heating.
What Causes Heat Pump Freezing?
A logical explanation for the outdoor coil to accumulate ice would be cold winter temperatures. In reality, the coil is typically much colder than winter air. When ice builds up on the coil to where it’s easily visible, the cause for ice accumulation is generally a mechanical, refrigerant or airflow issue.
- Mechanical: Heat pumps use defrost mode to melt ice on the outside coil. A failed relay or other component may be preventing defrost mode. Or, simply worn electrical contacts can stress the system and cause ice accumulation. A failing compressor won’t be able to process and prepare refrigerant efficiently or properly.
- Refrigerant: Too much or too little refrigerant can cause ice accumulation. Low refrigerant indicates a leak somewhere in the lines or coil.
- Airflow: Airflow may be obstructed by debris on the cabinet or coil, a recent snow or ice storm or perhaps ice forming from a leaky gutter dripping on the cabinet. If an obstruction allows a little ice to form on the coil, it could quickly get out of hand.
Quick Fix or Call a Pro?
During defrost mode, the thermostat will indicate “emergency” or “auxiliary” heat. This means the backup electric resistance heating elements are engaged to supplement home heating. When defrost mode is finished, the heating elements shut off and the heat pump resumes normal heat-mode operation.
If you suspect defrost mode isn’t working, switch the heat pump to cool mode. This sends hot refrigerant through the outdoor coil to melt the ice. Once the ice is melted, resume heat mode. If the ice returns, you’ve got a problem that requires the help of an HVAC contractor.
For more expert tips about your frosty heat pump or other HVAC concerns in your Wake Forest or Garner home, please contact Air Experts today.
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