Our office frequently receives phone calls from alarmed customers during cold mornings regarding their heating system not operating properly. However, after our staff hears the information, we explain their system was running correctly after all! Most people are unfamiliar with the defrost cycle of a heat pump. What the defrost cycle is, why it happens, and when you need to call to have your system looked at will all be explained in this article.
What is the Defrost Cycle of a Heat Pump?
When the temperature of the outdoor coil dips beneath 32⁰ the defrost cycle can occur. This happens because at this temperature frost may produce on the coil. Frost on the coil can cause damage to the system if not removed. Therefore, the system automatically changes to the cooling cycle. Raising the temperature of the outdoor coil. You might hear the reversing valve shifting the system from heating to cooling mode. Furthermore, the outdoor fan will not be running. The unit will only operate in defrost mode for a short period of time. Your indoor temperature should not be affected. The system will shift from the defrost cycle to normal operation until frost on the coil is not a risk any longer.
Defrost Cycle Signs.
The defrost cycle of a heat pump is a valuable action. On a cold evening or morning, it’s common for your system to switch into the defrost mode several times. You should begin to recognize the defrost cycle’s characteristics. As stated earlier, at the beginning of the defrost cycle of a heat pump you may hear the outdoor unit’s reversing valve switching from heating to cooling. Also, you’ll hear your indoor unit running, but the outdoor fan will be off. If you notice any new unusual sounds or see any other functions out of the ordinary have your system checked.
Is There Something Wrong with my HVAC System?
Have your system checked if it is running in the defrost cycle during mild temperatures. The defrost cycle of a heat pump should only take place when the coil temperature drops lower than 32⁰. If it is a 50⁰ day, your system should not operate in the defrost cycle. Likewise, if your system is running in the defrost cycle for a long period there might be an issue. A typical defrost cycle will only last for 5-15 minutes on average until it switches back. Contact O’Brien to diagnose any concerns you may have about your heating system running in defrost.
Contact O’Brien Service Company.
We hope this helps you understand the defrost cycle, recognize when it happens, and why it’s necessary. If you have any questions regarding the defrost cycle signs please don’t hesitate to contact our office. And remember on a chilly winter morning, don’t be alarmed by the defrost cycle signs. Your system was designed to operate in the defrost cycle!