Introduction
A contactor is an important component of a heat pump, used to control the flow of electricity to the compressor and the condenser fan motor. The contactor is a switch that allows high voltage power to flow to the compressor and the fan motor when the thermostat calls for cooling. In this article, we will discuss how a heat pump’s contactor works.
What is a Contactor?
A contactor is an electrical switch that is used to control the flow of electricity to the compressor and the condenser fan motor in a heat pump. It is typically located in the outdoor unit and is operated by a low voltage signal from the thermostat.
How Does a Contactor Work?
When the thermostat calls for cooling, a low voltage signal is sent to the contactor. This signal causes the contactor to close, allowing high voltage power to flow to the compressor and the condenser fan motor. When the thermostat reaches the set temperature, the low voltage signal is removed, causing the contactor to open and stop the flow of high voltage power to the compressor and the fan motor.
Parts of a Contactor
A contactor is composed of several parts, including the contacts, the coil, and the housing.
Contacts: The contacts are the parts of the contactor that make and break the electrical connection. They are typically made of silver or silver-cadmium alloy and are designed to handle high current loads.
Coil: The coil is an electromagnet that is used to open and close the contacts. When a low voltage signal is sent to the coil, it creates a magnetic field that pulls the contacts together, allowing electricity to flow. When the low voltage signal is removed, the magnetic field collapses, and the contacts are pulled apart, stopping the flow of electricity.
Housing: The housing is the outer casing of the contactor and is designed to protect the contacts and the coil from damage.
Potential Problems with Contactors
There are several potential problems that can arise with a heat pump’s contactor, including contact welding, contact pitting, and coil failure.
Contact Welding: Contact welding occurs when the contacts become stuck together due to arcing. This can cause the compressor and the fan motor to continue running even when the thermostat is not calling for cooling.
Contact Pitting: Contact pitting occurs when the contacts become eroded due to arcing. This can cause the contacts to become less efficient at conducting electricity and can lead to premature failure of the contactor.
Coil Failure: Coil failure can occur due to a number of factors, including overheating, age, or electrical surges. When the coil fails, the contactor will not be able to open or close properly, preventing the compressor and the fan motor from functioning.
Conclusion
A contactor is an important component of a heat pump, allowing high voltage power to flow to the compressor and the condenser fan motor when the thermostat calls for cooling. It is composed of several parts, including the contacts, the coil, and the housing. Potential problems with contactors include contact welding, contact pitting, and coil failure. By understanding how a heat pump’s contactor works, you can better diagnose and repair any issues that may arise with this critical component.
No comment