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Re: Sears air compressor starting problem

I have a 10 year old Sears air compressor (919.153131) that has ALWAYS

> given me a problem. I've just been too lazy to try to fix it. When > there is pressure in the tank, the compressor will not start. > > When there is no air pressure in the tank, the compressor will start > and work just fine. Then, when the upper air pressure is reached, the > compressor shuts off as normal. However, when the pressure in the > tank drops to the low set point, the switch kicks in and the > compressor motor tries to start - but nothing happens. > > The motor hums and turns a couple of times but here just doesn't seem > to be enough power to make it run. Then, after just a few seconds, > the breaker will trip. > > I am running it on a 15 amp breaker in my house and I have tried to > run it on 15 amp circuits at other houses - same problem. I am NOT > using an extension cord. > > Any suggestions?? >

Yeah: Twenty amp circuit. Seriously. Been there, done that, though not with the identical model (mine is 25 years old, give or take). Try that before you decide to spend money/time on the problem.

Jim Stuyck

Reply to
Jim Stuyck
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two thing come to mind the circuit cant handle the start up load of the when restarting with air in the tank. Is is in a dedicated circuit? have you tried useing a different plug on a different circuit maybe one that is closer to the service box. or the check valve has failed and or leaking keeping the pump under presuure / load making the restarting harder thus the need for more amps to restart and the circuit cant handle it.

Reply to
Dr. Doctor

replace the check valve.

Reply to
Dan G

Hey Jim,

Why would a larger capacity circuit breaker allow a motor to start instead of stalling? I don't think so. Just lets the "stall" continue for a few more seconds.

The compressor needs to start "unloaded", and it seems to do that OK with zero pressure in the system. It seems apparent to me that the compressor unloading valve is not working when the control opens at the high pressure set-point. So it traps the high pressure air in the compressor cylinder and keeps it on BDC, thereby stalling the motor.

Take care.

Brian Laws>

Reply to
Brian Lawson

Reply to
Barry Criner

Fellow wrote that the circuit breaker tripped. Mine did, too.

Now, if the fellow plugs his compressor into a 20-amp circuit, and that does NOT cure his problem, well and good. Nothing ventured, nothing gained. But if it DOES restart, then he's spent nothing but a few minutes.

Like I wrote, 25 years ago a 15-amp circuit, which SHOULD have been sufficient, was not. Switched to a 20-amp circuit and haven't had a problem since.

Jim Stuyck

Reply to
Jim Stuyck

It's not just the breaker, it's the wiring to the outlet. The higher capacity means bigger wires, so less voltage drop in the feedwires for the same current. That gives a little more oomph when starting.

Still, the right answer is probably:

Reply to
Pete Becker

No being familiar with Sears. Is this an oil or oil less?

I have an older Emglo, 15 amp, oil. From factory they put 30w oil in it, it would start up with no air in it, then do the same as what yours is doing. Hum until it would trip the breaker. Drained the oil, put in

5w30 in it, no problems for at least 8 years.
Reply to
Jim Nitz

I say its the check valve it the problem...... the check valve on mine went out and did the same thing(overloaded the motor) if it was the unloader not working even without air in the tank a defective unloader would not let the compressor start and would draw too many amps and blow the fuse or set off the circuit breaker.....

Reply to
jim

It COULD be either one! Some compressors are "self-unloading" and depend on the check valve to keep the pressure from coming back. Those using an unloader valve depend on BOTH. My Craftsman oilless started doing that after transporting it, found the 1/4" tube to the unloader had been bent, moving the unloader so it didn't activate when the switch shut off the motor. Result: blown breaker. Readjusted unloader bracket, it's been fine ever since.If the check valve were bleeding a little pressure back through, the unloader valve should handle keeping it bled off until startup time. Nahmie

Reply to
Norman D. Crow

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