Why does my contactor make a humming noise?

Three of the most common causes of these sounds include insufficient current from the control source to pick up the electromagnetic coil, incorrect voltage supply to the coil, and/or debris on the active components, i.e. the pole faces of the armature and yoke.

Should a contactor hum?

ANSWER: Chatter, humming or buzzing coming from a contactor indicates a problem and should be investigated.

Why is my AC compressor humming?

Your compressor works to pressurize and cool the refrigerant found in your unit. If your unit is making a buzzing noise then this means that it’s not doing it properly and you need to have it looked at. It could also mean that the electric voltage that’s running through your outdoor unit isn’t at the right amperage.

Why is my contactor chattering?

Low voltage to the contactor coil will allow the contactor to chatter. Contactor chatter can also occur due to chattering switches or loose connections in the control circuit. A low voltage situation can also occur due an unbalanced loading of the motor.

What would be some possible causes of a compressor motor humming when the contactor is closed?

One possibility is that the contactor relay switch may not be working correctly. This component controls how the electricity gets to the compressor. If it’s malfunctioning, power and amperage may be impacted, and you may hear the buzzing sound. The easiest fix is usually to replace the contactor relay switch.

Why is my AC humming but not working?

If the fan doesn’t start running, you may have a bad fan motor. If you have difficulty getting the blades to turn, there may be debris wrapped around the fan axle, or the motor bearings may be dirty or jammed.

How do you know if a contactor is faulty?

A bad AC contactor can be identified by physical signs of deterioration, also known as pitting. Pitting occurs when the contactor has encountered extreme voltage and heat. A pitted contactor tends to stick, causing a continuous flow of electricity to the unit.

How do I stop contactor chattering?

A shading coil is required to prevent chattering. The size and shape of a shading coil will vary depending on the brand of contactor.