20 Most Recent Craftsman 15 gal Air Compressor 3 hp UMC Horizontal k Oil Free Pump Questions & Answers

it seems like you might be adjusting a valve before the regulator. the outlet pressure from the compressor vessel should remain celatively constant. if you are adjusting the pressure whilst using the airtool and when you stop the regulator gauges return to/or close to/ the 150 PSI then this also points to you not adjusting the regulator.
Some compressors have 2 outlets... one regulated and the other not.

Craftsman 15 gal... | Answered on Feb 11, 2018

It sounds like a contaminated regulator, possibly due to moisture if you have never drained the tank. If it is a cheap air compressor then the best course of action would be to install another regulator as it is not worth the time to try to rebuild the regulator as most likely it is not a quality part. I would look into Wilkerson or Speedair brand parts to fix your issue.

Craftsman 15 gal... | Answered on Jun 05, 2015

Just fixed my compressor. It would start ok when the tank was empty but trip the breaker if it tried to start with pressure. Searched and read about weak caps, or problem with check valve or pressure switch leaving pressure in the pump head, etc. Turned out that the black plastic box which holds the 2 start up caps and is attached to the end of the motor with 2 screws had cracked on the bottom. The black box had tilted out enough that the start up caps switch was not engaging. Pushed on the lower part of the box and it started perfectly. Fixed it for the cost of some 2 part epoxy. Maybe not your fail, but definitely worth checking out first.

Craftsman 15 gal... | Answered on Feb 04, 2015

if less than 1 yr old you ca get a full refund if you are a craftsman club member. you must take it back to the same store where you bought it at and get a manager from the store to help you. it sounds like the head gaskets blew or the rings failed.I just went through the same thing with a different model of craftsman compressor ,so thats how i know what can be done. They will only help you out if the compressor looks unabused in any way.if its oily leave it that way so they can see its an internal failure. good luck.

Craftsman 15 gal... | Answered on Apr 18, 2013

The regulator will have an arrow cast into the body indicating the direction of air flow.

Craftsman 15 gal... | Answered on Nov 02, 2012

If all is well where you say it is the next thing I'd check is the condition of the piston & cylinder then the valve plate. On oilless compressors it's common for the ring on the piston to get worn or have peices come off. It may or may not damage the cylinder but it will be able to compress air until the pressure is too high for the leak past the piston to overcome. Also if the valve plate got overly hot the reed valves may warp or break off, again letting the pump compress air only to a point then the internal leak will prevent it from getting high enough for the motor to stop and cool down.

Craftsman 15 gal... | Answered on Jul 11, 2012

The UMC Series units do not take oil. These units are oil free.

Craftsman 15 gal... | Answered on Mar 30, 2012

Hi gregtrulu...
Go to the Sears direct website and you can chat with them,email them, or have them phone call you.
You will ask them about the user manual that you want for the 919.164180 compressor you have
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Craftsman 15 gal... | Answered on Sep 11, 2011

Normally a petcock valve is closed when the handle is PERPENDICULAR to the flow.


=====----===== (Open)
====='===== (Closed)

Craftsman 15 gal... | Answered on Sep 06, 2011

Hi dtsorrell...

If your somewhat of a mechanic/electrician then you can by-pass the pressure switch by hooking the color coded motor wires together with the incoming color coded wires from your power cord in the proper order.
Plug it in and then check to see if it blows the breaker again, if it does then it is your motor that is faulty.
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Craftsman 15 gal... | Answered on Jul 28, 2011

Hi, my name is John. Welcome to FixYa. Will it come on at all? Check the outlet circuit breaker, if it comes on at all, check where the line comes form the pump to the tank, there got to be a leak, you may have to remove it in order to check under it. Check for a reset button next to the wire coming to the switch. Thanks for choosing FixYa...John

Craftsman 15 gal... | Answered on Jul 09, 2011

There is a check valve that has gone bad,this allows air into the tank,and does not allow the air to go back toward the compressors head.This can also cause the compressor to lock up.

Craftsman 15 gal... | Answered on May 17, 2011

This sounds like the gage is out of calibration. 50 psi sounds about right for this model. I believe 120 psi is max press. and it should pop the safety at 130 psi. Drain the tank, it has a drain at the bottom of the tank. Remove the gage from the fitting. It should read 0 with it out of the system. If it does not read 0 she is out of calibration. I do not believe this gage can be calibrated back to 0 if it is sprung. You will have to find a new one or do the math in your head. If the gage does go back to 0 once removed. Your regulator is bad, you can try to rap it with a hammer handle to see if that will get it back in line. Next step would be to replace the regulator assy. Hope This Helps Fix Ya up.

Craftsman 15 gal... | Answered on May 17, 2011

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