919.164200 not running properly

by Phil D.
(Pittsburgh, PA)

I have a Sears Craftsman compressor, Model #919.164200, 4.5HP 20Gal Oil Free that is not running properly. Don't know the age, as I picked up second hand for free, but it was not abused and still looks very new. DeVilbiss, Serial #990215278. Testing this morning revealed these issues which I hope will provide a proper diagnosis of what the problem is and what needs to be done to fix it.

Let me apologize from the start of my lengthy explanation, but I want to be sure that I don't leave any detail left out to assist in a proper diagnosis.

-Plug compressor in, switch off, no problems.
-Throw switch from OFF to ON, compressor motor starts and functions properly.
-Unit continues to run and fills tank with air.
-Tank reaches level of 140 PSI, pressure switch kicks in and shuts motor off.
-Using an air-gun, drained air from tank.

*-As air is drained from the tank, the pressure switch kicks back on but the motor hums and DOESN'T
start back up.
-If I throw the switch to OFF, it shuts back down, when the switch in thrown back ON, it still hums.
-If I don't catch it in time when the motor hums, it throws the breaker.
-With the compressor switch OFF, when I use the air gun to drain the tank to 100 PSI and throw the
switch to ON, it starts up no problem.

-I tested the compressor in several other ways...
-From a cold start, with tank empty, compressor was started, allowed it to run and build pressure.
-During this stage of operation, prior to it reaching full tank pressure, I switched the unit OFF & ON
several times, no problems during this test.

-My problems seem to be when it reaches full pressure and try to restart.

Is this a Start Capacitor issue?
Is this a Pressure Switch issue?

Any advice to GREATLY appreciated to solve my problem.

Thank you. Phil Pittsburgh, PA

Comments for 919.164200 not running properly

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Jul 07, 2017
Back pressure stalling
by: Paul

This is an NRV (non-return valve) fault, basically it starts with no pressure ok but when it's up to pressure the non return valve that holds the air in the tank is back feeding, as it's not sealing the air in the tank

or your delivery pipe vent down (unloader valve), usually at the base of the pressure switch is not venting the air delivery pipe to the nrv.

So it stalls the motor as it cannot provide enough torque to drive against the psi in the pipe.

Run it up to pressure and when it switches off isolate the power and undo the delivery pipe. If there is a slight release of air it's a vent problem (so new pressures switch) if it continues to release air then the nrv seal has failed so new nrv.

Jul 03, 2017
919.164200 won't restart normally
by: Doug in s.d.ca.

I do have a strong suspicion that this is the pressure switch. However, I'd like you to look at the following to help you not waste money on one before being sure.

Please check the capacitors. They may be OK, but can't know for sure unless you test them.

Start here:


If need be, ask, and let us know what you find, please.

Good luck.

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