3 Reasons for an Air Compressor Leaking Pressure Switch

This video goes over a few main reasons why your air compressor pressure switch or unloader is leaking while the compressor is running, or when it shuts off. This also explains how to diagnose the issue.

[danielasal]

Awesome! You settled an argument and, answered all my questions even without me having to ask. Thank you so much.

[andrewdreszer]

If you have replaced the check valve and replaced the pressure switch and still have air leaking through the unloader valve on the pressure switch, then you may need to make a slight adjustment in the clearance between the pin at the end of the unloader valve and the paddle switch. I had this problem with a switch on a Senco 0968 compressor that is like the black one in this video. The pressure switch has a small lever or paddle that pushes a pin at the end of the unloader valve when it shuts off. If the unloader valve leaks air after the compressor shuts off and keeps bleeding the pressure down to zero through the unloader valve, check the adjustment between the pin and the paddle. There is a nut just behind the pin on the unloader valve that offers some adjustment and there is a screw that secures the unloader valve to the pressure switch housing that also offers some adjustment. The adjustment needed is slight but it can correct the leak and allow the compressor to hold pressure. Worked for me.

[lewdennis]

Thanks for the video! You helped me find a bad check valve on my 30+ year old Craftsman 4hp compressor! First I changed the pressure switch, which wasn’t the problem. Now waiting for the new check valve to arrive.

[fartenfreddy]

Thanks, old guy here no clue. Vid explained why #3 my chevk valve was the problem. The valve turned out to be serviceable, cleaned it out, all good.

[crawling]

If you have a general air product and you've changed out multiple pressure switches and you can't figure it out! it is at the end of this video thank you so much sir respect

[donaldspencer]

Thanks! After many videos yours is the one that answered my question.

[jerrymeeuwse]

You answered my question perfectly. Mine was leaking only when the compressor Was running from underneath. I replaced the original switch about 3 years ago and bought a cheap replacement. Go figure.
Thanks again.

[herodVII]

On a couple of occasions I had to lightly sand and oil the side of the rubber stopper in my check valve when leaking after pressure switch shuts off. The rubber seems to expand and get stuck in the housing nut/cap. It works fine as long as it slides easily within the valve.

[WALLACE]

I just had problem 2 you said needs a complete new switch, I took the valve out cleaned it and works fine now.

[wiggymccrackin]

Wow! Very informative video I did not expect to get all my answers on YouTube let alone one video. Thank you for making this!

[frankcadena]

I need a check valve (compressor only leaks from the switch when off) for a Craftsman Sears Craftsman 919.167320. What part number do I look for on your website? Does it come with a removal and installation guide? Thanks.

[lenardprice]

Sir I have a husky air compressor where can I get a replacement one ( valve switch is where it leaking)

[broady]

Hi I have a wolf professional 90 litre . It is brand new only used it a few times and my switch is leaking when I pull the switch up to switch it off.
Is it normal for them to go wrong as soon as that??

[ionutemanoinicolae]

if my air compresor pressure switch does not have cut in pressure can i change it with another pressure switch witht cut in an cut out? It is like this from factory.

[rickspohn]

I have an Ingersoll Rand, single stage, 5hp, 60 gallon upright compressor. It just started leaking under the pressure switch. Max pressure is 125 psi but when it reaches about 100 psi the leaking stops. I replaced my check valve but this did not solve the problem. Any other suggestions? Do you think my pressure switch is bad? Thanks.

[tyrondeau]

Thanks. Very helpful. I will be removing my check valve.

[miguelguerra]

Hi. Is the ckeck valve aka relief valve?

[michaelgarofalo]

So I have a question I replaced the check valve and the unloader but my switch still leaks air once it gets up to pressure i can see it activate the loader once it gets pressure in the tank about 80 psi and stays on till around 20 then it shuts off

[skipper]

Could it also be the regulator manifold?

[kennethweilbrenner]

I replaced the pump on my Campbell Hausfeld 80 gal/175psi, 2 stage pump with has a check valve on the hose between cylinders. The new 2 stage Harbor Freight pump 145psi has no check valve. I lowered the max cut out pressure 3 turns CCW on switch. Ran pump up to 140psi and shut off. Unloader valve releases air when shut off until pressure is lowered to around 120 psi. Is this just fine tuning of the switch adjustment or do I need to add a check valve?