My Hitachi pancake style air compressor has been acting up – after compressor kicks off, I heard a load air release for about 5 seconds. At first I thought that the connection to the hose wasn’t secure, so I replaced it, but now I see the air is coming from under the pressure switch.
Seems there is an “unloader” that allows some air to escape, and this is activating when the compressor gets to full pressure and the motor turns off. It got to the point today where it lets so much air escape, then it goes below 90PSI in the tank and turns the motor back on. The cycle is motor on for 15 seconds, motor off, air escapes for 5 seconds, motor on for 15 seconds, etc.
The switch looks like this one http://www.mastertoolrepair.com/port-style-p-10029.html
There is a hose that connects from a “non-return valve” to the pressure switch. Is it safe to remove this and block the valve? What does the unloader do? There is a high pressure safety valve attached to the tank, so I am not sure if this contributes to safety or performance. Any suggestions?
Replies
The unloader valve releases pressure form the compressor head and cylinder so that the compressor doesn't have to start up against pressure.
Yes it is important, Yes you need it.
Unplug the compressor, drain the pressure from the compressor, remove the valve, clean it and replace it. If this doesn't solve the problem it is time for a new valve.
I have purchased a few for my compressor(different brand) from my local Napa parts store.