Heat Pump Freezing Up? Troubleshooting Tips to Keep Your Heating and Cooling Running

by Greg Leisgang on May 6, 2014

Posted in: Heat Pumps

heat pump freezing upHeat pump issues, such as the coil freezing up, can quickly hamper heating and cooling performance and place strain on other components. If ice accumulation has occurred on the outdoor coil (heating mode) or indoor coil (cooling mode), use these tips to see if you can remedy the problem before calling your trusted HVAC technician.

Heating Mode

Air-source heat pumps provide heating and cooling for the home by manipulating refrigerant with pressure changes to extract, move and release heat energy. In heating mode, the refrigerant inside the indoor coil becomes exceedingly hot and transfers heat energy to indoor air. The outdoor coil, in heating mode, becomes exceedingly cold in order to absorb heat energy from very cold winter air.

However, the cold outside coil isn't the reason for ice accumulation. These are common causes and troubleshooting tips:

  • Airflow - The coils must receive free airflow to instigate heat exchange by the refrigerant. Make sure the outside unit doesn't become covered with ice, snow or any other debris. A lack of airflow across the coil will cause ice accumulation.
  • Refrigerant - Incorrect refrigerant charge, either too much or too little, causes ice accumulation. Call your HVAC tech to remedy this issue.
  • Demand defrost - It's possible that the demand defrost mode isn't functioning correctly, which is another issue for an HVAC professional. There may be a faulty reversing or relay switch.

Cooling Mode

In cooling mode, the heat exchange and refrigerant temperatures reverse. The indoor coil becomes exceedingly cold and absorbs heat energy from indoor air to cool it. Again, however, this isn't why the indoor coil freezes up.

  • Airflow - Check the air filter. A clogged air filter blocks airflow and causes the condensate on the indoor coil to freeze. Soon, there's a snowball effect and your house begins to heat up. Turn off the heat pump to allow the ice to melt.
  • Electrical contacts - Worn electrical contacts stress the compressor and other components, which can create ice accumulation.

If you're having heating and cooling issues in your Morrow or Springdale home, contact Tri-County Heating & Cooling.

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