Heat pumps do ice up in winter. It is normal for the entire coil to be covered in a white frost or even light ice during certain weather conditions. Heat pumps will naturally ice up in winter but will periodically go into a defrost cycle to defrost the coils. This keeps the unit running efficiently.
It is not normal however, for the entire unit to be encased in ice for an extended period of time. Proper heat transfer between the outside air and the freon can not occur if the coils are blocked by ice. This would indicate a problem and should be addressed.
Different heat pumps have different ways of determining when to go into defrost. Some are mechanical; others use solid state controls with temperature sensors but all must go into defrost to keep from icing up.
There are many other reasons why a heat pump can ice up. Listed below are some of them. Items in blue can be addressed/or fixed by the homeowner. Those in red usually require a service call.
- Outdoor coil blocked-possibly with leaves or snow.
- Leaking gutter dripping water onto top of unit.
- Freezing rain-causes top of unit to freeze over. If this happens rest of unit will also freeze over.
- Defective defrost control or timer.
- Defective defrost thermostat or sensor.
- Defective defrost relay.
- Sticking reversing valve.
- Defective reversing valve solenoid.
- Defective outdoor fan motor.
- Low refrigerant charge.
- Refrigerant restriction
Hope this has been of some assistance, however they are just rough guidelines and not all possible conditions are covered. If you’re unit is iced-up solid, go to your thermostat and switch it to emergency heat. Depending on the capacity of your electric heat strips, this may provide enough heat to keep you comfortable until you can have your unit serviced.
Remember: The company You Choose To Install and Service Your System Will Determine The Degree of Comfort and Satisfaction You Enjoy. Call Hammond Services if you need service in the Griffin, Ga and South Metro Atlanta area at 770-227-5325. Check out our website at http://www.hammondservices.com.