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.

[@andrewdreszer6351]

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.

[@danielasal2783]

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

[@lewdennis3226]

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.

[@crawling86]

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

[@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.

[@donaldspencer5407]

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

[@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.

[@WALLACE7084]

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

[@jerrymeeuwse859]

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.

[@blakesnow1308]

Very helpful video thank you

[@liamrobinson2084]

Thanks for this informative video!

[@louisgl]

Great video! it helped

[@wiggymccrackin8240]

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

[@GreatBowlsAfire]

fantastic help.. thank you! :D

[@frankcadena9293]

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.

[@rashminanda112]

Thank you sir

[@tyrondeau8621]

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

[@guyzoun]

Thank You!

[@rickspohn6879]

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.

[@kennethweilbrenner4919]

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?

[@skipper199608]

Could it also be the regulator manifold?

[@broady42]

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??

[@michaelgarofalo4452]

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

[@lenardprice6813]

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

[@mondgo8866]

Nice vid.. really helps.. thanks!

[@ionutemanoinicolae4514]

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.

[@SubtleMischief]

Thanks for such an informative video. All hail the Algorithm

[@praveenkumar-ke1pn]

It could chenged the u/l valve and diaphragm also,and if yes you want sell your whole pr. Switch than its also fine

[@miguelguerra1927]

Hi. Is the ckeck valve aka relief valve?

[@maximsels8621]

Nice video! I had (have) problem 3, the thing is I replaced the check valve and still have the same issue... Any clue what happened? Thanks in advance

[@65csx83]

Were you able to remediate the problem? He doesn't mention it in the video but problem #3 could be confused with a leak elsewhere such as a leaking drain or pressure relief valve among others.

[@user-ve7mg5bo7p]

Nice

[@Tonyplat98]

I have a leak on the under side of the pressure switch it's the valve stem that's leaking. Is there a way to seal that off?

[@diehardfan173]

2:58 I Thank you very much!

[@dan102061]

I just replaced my precious switch on my campbell house field compressor. I turn the compressor on and it fills up to a 120 P, S, I, then shuts off.....then the unloader starts leaking until the pressure drops to 100 psi then it stops leaking????????

[@paulreesor8200]

Put up with it for years now replaced the switch and now realize it's the check valve if you're correct..

[@mmcauley65]

Problem #1. Thanks mate saved me a lot of f**king around

[@douglasgardner2756]

I have problem #3. If I turn off the compressor or, it hits the `150PSI max and shuts off there is a valve inside the switch that pops open and bleeds down to about 80 PSI then the valve closes and compressor cuts on and repeats the cycle. It is interesting that when I turn off the compressor via the top switch it makes the valve within the switch open and bleed out. My Sears parts list has a Tank Safety valve and a valve bleeder. Please let me know which you feel it is or both that need to be replaced.

[@kenel1975]

Same here ... did you figure anything out?

[@douglasgardner2756]

@@kenel1975 I replaced the check valve which fixed the problem. I also replaced the drain valve at the bottom of the unit since it was rusted and when opened would not seal properly.

[@albertlosacano6054]

My compressor constantly Runs will not build air pressure is the adjusting value the problem ?

[@brianramsey7171]

It only leaks air when you flip the switch to turn off compressor what could be the issue

[@fvrrljr]

Excelentemente aka super excelent separate the words excelente mente becomes excellent mind i Like, OLE!

[@mikeanderson4080]

Mines leaking from the diagram housing.

[@paulk5311]

check valve can cause it to leak when running or when it is off. if 2 and 3 can equal the air coming from the unloader then 1 can also as in this case 1 = 2+3. this video caused me to disassembly my pressure switch as it constantly leaked. well when i opened it up i noticed there was nothing wrong with it. now i have to put it back together. and no it is not that hard which is another thing this video got wrong.

[@eclipse1999able]

Hi when I first got my 150 psi compressor it would fully pump to 150 psi for maybe 2 months. Now when it pumps up it maxes out at 135 and cuts out. Which part should I be looking to purchase? Thanks

[@paulk5311]

you can adjust the maximum pressure that the switch uses to shut off.

[@IshfaqAhmad-cr7el]

❤

[@byronc7284]

My compressor will build up air but once it reaches Max pressure it'll leak air until compressor kicks back on, over and over again. I have to unplug it in "on" position to hold the air in. Once it turn to "off", it'll leak again

[@byronc7284]

@LAFOLLETTER Yes. I bought a check valve couple months back. It fixed my compressor. Thank you for your comment.

[@hamdieilish]

@@byronc7284 what did you buy ? And how can I fix mine because I have the same problem 😢

[@byronc7284]

@@hamdieilish check valve. That fixed it

[@mohammedhatim4976]

I’m having the same problems , I want to replace the check valve.its just difficult to get to it , it’s under the pump and the motor .

[@rikujkoivisto]

I have very differend unit.. (Strong Line.) 😳

[@JasonSmith-qx3zh]

CS mine builds air fills the tank and leaks out of the oil fill plug hole help !!!!!

[@glennedward2201]

How about piston rings being bad and leaking from pump exhaust. I can think of about 12 reasons they leak.

[@avflyguy]

Once the compressor shuts off, isn't that the check valves job to stop any air going back to the compressor and the pressure switch.

[@robertmedina6875]

Put a tip or paypal link for.tips

[@raakmore4443]

I have a compressor rated for 125psi but it won't build past 98 PSI. Could this be a leaking pressure switch?

[@eclipse1999able]

You ever figure this out? Mines a 150 psi but now only builds to 135. I'm leaning towards new pressure switch

[@raakmore4443]

@@eclipse1999able no i never did i sold it but let me know if you figure it out

[@eclipse1999able]

Raak more I installed a new check valve and pressure switch and it went straight to 150 no problem

[@snooginsivmf]

I have problem #3 so I bought a whole new switch and still having the same problem

[@BBRED721]

i did the same thing !!! is yhe check valve hes talking about is it the safety valve !!????

[@jaysontabia6894]

My pressure switch unloads air when reaching the max pressure. Is it normal?

[@tonyb2760]

Does it unload when you turn it off?

[@jaysontabia6894]

@@tonyb2760 Let say cut off is 110psi It unloads air about 100psi until I reach 110psi and it will take minutes to charge from 100 to 110psi. Pressure switch shut off at 110psi. No, it doesnt unload when pressure switch hits the cut off. I suspect that the unload valve cant hold air pressure beyond 100psi. Is is normal?

[@millermatic140]

As I’m new to this. I bought a used compressor that had a three phase motor and I later replaced it with a single phase. Do I need a different pressure switch?

[@rubenvazquez3101]

No sir, but the mag starter you will.

[@millermatic140]

Yup I got a new mag starter. 240 line is three wires two hits one ground. But I see 4 wires which I assume because it was a three phase set up

[@sofiavanikiotis7436]

it makes no sense what he is saying .if leaks when its on ,of corse will leat when its off ,what the hll

[@user-hm6cx7mc5l]

Makes perfect sense. If leak occurs only while working,it is because check valve is continuously opening and closing,as it should,allowing air to reach the unloader of the pressure switch,which leaks. So that is a good check valve and a bad unloader. Now,when the air compressor is off,the check valve will close,not allowing any more air to pass through,thus stopping the leak from the leaking unloader

[@PaulBrissonPUNTA_GORDA]

I didn't read through all of the comments, but it seems that you never discussed how to determine that it is the compressor switch that is leaking.