The compressor start relay is a device that let you know when your compressor has started, and when it is ready to be loaded. It can be used to help your compressors to last longer by making sure that they run as efficiently as possible. Since most compressors use very hot air to heat up the system, there is a possibility that the exhaust system of the compressor may overheat. The result is that if the compressor is running at full speed, it could cause the unit to overheat.
This has a knock on effect to the pipe leading from the compressor to the system. If the pipe is already over-heated, this may cause it to leak, causing even more damage to the system. The starting relay helps to prevent this from happening. If the exhaust pipe is leaking from the back of the unit, it may be too hot to run and will eventually be unable to start.
A compressor start relay works by acting as a sensor that alerts the compressor of a problem. The relay is controlled by a keyed switch. This means that it is easy to change the relay to a newer model whenever there is a problem with the one that is currently in use. Changing a start relay can also be very economical, since it can be replaced once a year rather than every three to five years as it would be with an older model.