Capacitor

BEFORE ATTEMPTING ANY REPAIR MAKE SURE ALL POWER HAS BEEN DISCONNECTED FROM THE EQUIPMENT

There are two different types of capacitors used on your HVAC unit. They are called a run capacitor and a start capacitor. The primary difference between the styles are a run capacitor is being utilized the entire time the unit is in operation and the start capacitor is utilized only during startup and then electrically disconnected from the circuit. The construction difference is the run capacitor has a smaller uf (microfarad) rating and is sealed in a can filled with cooling oil to prolong the life. A start capacitor has a greater uf rating and is sealed in a can that is air cooled.

Both capacitors also have a Volt rating. The volt rating is the maximum inrush voltage during operation. A capacitor with a higher volt rating can replace a capacitor with a lower volt rating.

A capacitor with a lower volt rating can not replace a capacitor with a higher volt rating. This will lead to a failure of the capacitor.

The most common capacitor failure is the run capacitor due to being online during operation and having a tendency to overheat during high load conditions when the surrounding temperature is high. The warmer the outdoor air the less cooling ability to cool the capacitor.

Capacitor should be flat on top. If it is even slightly domed it needs to be replaced. It is critical to replace it with the correct capacitor as using an under or overated capacitor can lead to motor or compressor failure.

The terminals on top of the capacitor are labeled Herm, Fan and C. This designates which wire goes to the Hermetic Compressor, outdoor Fan and the Common power line. It is critical to get the correct wire on the correct terminal or serious and expensive damage can occur.

We recommend taking a clear picture of the top of the capacitor before removing any wiring. If you are unsure consult a professional HVAC technician

If you need help identifying the correct capacitor when you are making repairs to your furnace, air conditioner, or heat pump you can call or email us and our staff will be happy to identify the correct motor capacitor you need