Compressor slows down during pump up

by Bob
(Wharton, Texas)

I have a 5HP electric Compressor. Compressor starts up fine, after compressor starts to build pressure around 70 lbs. or so compressor starts to slow down causing overloads to trip breaker.

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Bill says...

Bob, nice to hear from you.

As the compressor fills the tank, air in the tank makes it harder for the compressor to add more compressed air to the tank.

The check valve on the line into the tank may be failing, and perhaps it's blocking the ingress of the air into the tank, causing a load increase on the compressor head, overloads the motor, and pops the breaker.

Since this is the cheapest issue, check the check valve. Drain the tank and turn off the power first.

Other things that can cause this problem is lack of oil in the compressor head(it get's hot and starts to seize), there is a mechanical issue with the compressor head, or your motor is wearing out.

No way to diagnose it for sure from here.

Good luck.

Bill