Craftsman upright compressor is slow starting and blows breaker.
(Bossier City, La.)
I have a 30 gallon Craftsman upright. 919.167311 built in 2002. If there is no pressure in the tank it will run to about 100 psi, then it shuts off. It sounds like it is loading harder than normal as the pressure increases. If I cut it off at around 20 psi and then turn it back on the motor binds and trips the breaker. I don't know all the part names but I removed the small tube from the tank to the pressure switch and it ran like a champ. Dumping air obviously. I have been reading the blogs and assume it is the pressure switch. But am wondering, is the pressure release valve is in the switch box. Are we talking about the valve that has the ring on it that I can pull to release pressure. I call it a pop-it valve. Is the unloader in or on the side of my switch box/pressure switch? Any idea what the problem may be and can I clean or replace anything inside the 'pressure switch' if that is the problem. That thing is close to a hundred bucks and I'm cheap!! Do you recommend one from somewhere besides Sears.
Gary, a bunch of questions, for sure.
The pressure switch turns the compressor on and off at preset pressure readings. If, when the compressor tries to start, there is power running from the pressure switch to the motor, then the start side of the pressure switch is working. If the power flow to the motor stops when the pressure in the tank reaches the normal cut out pressure level, then the stop side of the pressure switch is working.
Pressure switches, typically, have either a small lever that juts out one side of them to operate the unloader valve, or have an internal unloader valve operating mechanism. It sounds like yours is the former. That unloader valve should be triggered by the pressure switch when the tank pressure reaches the cut out pressure level and shuts the compressor off. The dumps the air over the piston, allowing an easier restart.
You say "it will run to about 100 psi, then it shuts off". Is this the normal cut out pressure, or is the compressor stopping sooner that it should? Look to the pressure switch being the possible cause, if it is stopping sooner.
When empty, your compressor starts OK, but won't start under load. The first check I would make is to ensure that the unloader valve is actually working.
Check these out and post a comment here if we want to discuss your compressor further.
Craftsman 20 gallon upright air compressor wont start under load
My 20 gal upright air compressor (mod # 919-165230) is kicking breakers and not starting when there is even a small amount of air pressure in the tank.
I replaced the capacitor thinking it might be an easy fix. Still having the same issue. Based on reading some past comments, it appears that replacing the check valve might be the next step.
On the diagram, it refers to this part as the "choke valve"....not sure if that is something totally different, but seems to match up on part # searches. Any help on where to go next would be much appreciated.
Before you dive in, can you tell me, is the unloader valve working? Maybe you could post a comment here to let me know.