Won't turn off automatically

Unit starts whrn pressure is zero, but won't turn off.

____________________
Bill says....

Is it that your compressor turns on at low pressure cut in, then the pressure builds past the normal cut out level, and keeps running and building pressure until the PRV pops?

Or is it that the compressor pressure level builds to a pressure level below the normal cut out, and as a result, the pressure switch never senses the cut out pressure level and the compressor keeps running?

If the former, look to a faulty pressure switch.

If the latter, look to the TROUBLESHOOTING page about "COMPRESSOR WILL NOT BUILD PRESSURE".

Cheers.

Bill