Under normal operating conditions, your heat pump’s coils should never freeze up. A small amount of frost on the coils is normal, and the defrost cycle typically takes care of the frost. It’s helpful for homeowners to understand what role the coils play in the heating process, and why the coils develop frost, in order to know when to call for help when there is excessive frost on the coils.
The defrost cycle in action
Heat pumps have built-in controls to sense when frost or ice builds up on the coil, so that the defrost cycle activates to take care of the problem. Here’s how the process works:
- The reversing valve activates the air conditioning.
- The outdoor fan cycles off, while the condenser cycles on to perform evaporative duties.
- The unit sends refrigerant under high pressure to the outdoor set of coils.
- This refrigerant causes the coils to become warm, which melts the accumulated frost and/or ice.
- At the same time, the heat pump activates the backup heating element to temper the cooling effects of the air conditioning process.
- The outdoor unit utilizes a sensor and a timer or other control to allow sufficient time for defrosting before the heat pump’s normal heating operations resume.
The most-efficient defrost controls utilize high-tech sensors to read the outdoor temperature, refrigerant temperature and duration of the operating cycle to determine when to activate the defrost cycle.
Call the experts
When certain problems occur within the heat pump, the coil will freeze up. Most often, these problems require that homeowners contact an HVAC contractor for service. With a technician on the scene, he or she can determine the root of the problem, which could be the result of any of the following issues:
- A faulty timer or control
- A malfunctioning thermostat, relay or sensor
- A problem with the reversing valve
- Low refrigerant levels
- A bad motor
When you experience any type of problem with your heat pump, contact Amarillo Air Conditioning. We’re happy to help our neighbors in greater Amarillo with quality heating and cooling solutions, including maintenance and indoor air quality needs. Just give us a call or visit our website for more information.
Our goal is to help educate our customers in Amarillo, Texas about energy and home comfort issues (specific to HVAC systems). For more information about heat pumps and other HVAC topics, download our free Home Comfort Resource guide.
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