HVAC Overload Relay Replacement Parts

Overload relays are protective devices used in HVAC electrical systems to safeguard motors, compressors, and other components from excessive current or overheating. These relays automatically interrupt power when current exceeds safe limits, helping prevent equipment damage and ensuring reliable HVAC system operation.

A thermal overload relay operates using heat-sensitive elements that respond to current flow. When the motor or compressor draws excessive current, the relay heats up and opens the circuit to protect the equipment. Once the system cools down, some overload relays reset automatically, while others require manual reset.

HVAC systems use various overload relays, including thermal, solid-state manual, and auto-reset control units, and pole thermal relays. These devices protect motors and compressors during startup or heavy loads, ensuring safe electrical operation and preventing equipment damage.

Technicians should check symptoms such as compressor shutdowns, motor overheating, frequent tripping, or delayed system startup. These signs often indicate that the overload relay may be worn, incorrectly rated, or experiencing electrical stress within the HVAC system.

PartsHnC supplies HVAC overload relays, including bimetal thermal overload relays (24V–120V), compressor overload protectors, motor overload protection relays (120V–480V), electronic overload relays (120V–600V), phase failure overload relays, and adjustable current overload relays from trusted brands like ABB, Siemens, and Danfoss, with fast nationwide shipping available.

How do I reset a thermal overload relay after it trips?

Allow the relay to cool down completely before pressing the manual reset button. Some models reset automatically once the internal temperature drops to a safe level.

Why does a compressor overload protector keep tripping?

Frequent tripping may indicate compressor overheating, high current draw, restricted airflow, or a failing compressor motor.

How do phase failure overload relays protect HVAC motors?

These relays detect phase loss or imbalance in three-phase power systems and shut down the motor to prevent overheating or electrical damage.

How can I test a motor overload relay with a multimeter?

Disconnect power and check continuity across the relay contacts. If the contacts remain open or show abnormal resistance, the relay may be faulty.

Can a faulty overload relay stop an air conditioner from running?

Yes, if the relay trips due to excessive current or overheating, it will disconnect power to the compressor or motor.

How do I know if an AC overload relay needs replacement?

Signs include repeated system shutdowns, overheating motors, burnt relay smell, or failure to reset after cooling.