Check valve for compressor

[benchracer1]

Got an old ingersoll rand t30 compressor. It's the type with the large washers as check valves. The thing is great but after 3 or 4 days not used the tank pressure drops to zero. I can hear a leak back through the compressor head. Tank itself has no leaks. I was looking at installing a one way check valve in the 3/4 line that goes to the tank. How large of a check valve should I install so it doesn't create an obstruction to airflow....Steve

 

[WillyBoy]

I'm not familiar with this specific compressor model but I'd be surprised if there isn't a check valve in the discharge line going into the tank. This allows the line to be depressurized by the unloader valve so the compressor isn't trying to start against full tank backpressure.
I'm not sure that the discharge valves in the head are intended to hold full tank pressure continuously.
I'm sure others more familiar with this model will be along shortly.

 

[micromind]

Look up 'Load Genie'.

These are in-tank combination check valves and unloaders.

Easy to install, in fact there might be one on your compressor already and it has failed.

 

[Spareparts]

Might be just dirty, especially an older unit

 

[no704]

3-4 days? I would never expect pressure to stay for that long. It’s not a car tire.

 

[benchracer1]

Not the best Pic. If I remember I pulled this fitting from the tank a few years back and it was just a reducer bushing. Perhaps it is supposed to be a check valve.

 

[micromind]

The middle has in the pic could be a load genie. They are small like that, the actual valve is inside the tank.

If you can see all 6 sides and one of them has a small hole, it's a load genie.

In my experience, they usually fail in the open position, meaning that the check doesn't block reverse flow. Often, the small hole will leak air, running or not.

The center hex could easily be part of the copper tube fitting and not a valve at all.

 

[pcmeiners]

Tank check valves are very high friction junk, bean counter engineered valves. If you want a real check valve, check out the link below. With check valves you are better off getting an oversized valve and using bushings down to your compressor pipe size, to cut down on friction. This check below goes for approx. $200 full retail......

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Threaded In-Line Check Valves

The DFT® Model SCV® is a corrosion resistant, dependable, versatile and economical spring-assisted, in-line check valve for a wide range of applications. Whether the fluid is liquid, gas or steam, the SCV® provides tight shut-off and prot

catalog.dft-valves.com

 

[benchracer1]

Absolutely no check valves between 2nd stage and tank. Found this between first and second stage.

 

[racecougar]

3-4 days? I would never expect pressure to stay for that long. It’s not a car tire.

An air compressor should be able to hold pressure a heck of a lot longer than a few days.

 

[benchracer1]

I cleaned up the valve and it initially was fine. I came out this morning and the tank was down about 50psi. I pulled the line loose and sure enough the valve is slightly leaking air.

 

[KenC]

Last time I needed one, I searched several local stores and finally remember Grainger. They have a big selection in stock and reasonably priced. I would use one at least the same size as the delivery tube/pipe or one size larger with a reducer.

 

[73project]

I just replaced one of those on my Quincy 60 gallon compressor. I got my replacement from eBay that was a US made part for my compressor. It was less than $20 and is working perfectly. Find the manual for your compressor to get spare part numbers, and then search for that number. I saw the cross reference number for my valve listed anywhere from $59 down to $16 for the same valve.

 

[benchracer1]

It's not a hugely common compressor. I'm going to try and locate a parts manual. It's kinda annoying to go to pump up a bicycle tire anhave to pump up a 120 gallon tank.

 

[john.k]

Check valves in the discharge heat up red hot as well as obstructing the air flow ........every obstruction robs output capacity................If I had a compressor that held air for 3 days ,Id be very happy ............overnight is better than good IMHO ...............id suggest a cordless to pump your bicycle.

 

[racecougar]

Again, if your compressor loses its charge in a week, heck, in a month, that is not the norm.

 

[benchracer1]

I'm trying to find a replacement check valve but no luck.

 

[benchracer1]

The check valve leads to the crankcase then comes out of the case and goes to the first stage then to atmosphere.

 

[john.k]

The only air tanks where pressure is held for long periods is truck air start tanks ........owners go to a lot of trouble to be sure they have enough air for a cold start when the temperature is low .

 

[racecougar]

...and air compressors, and many others.

 

[dave*99]

This is the check valve on my Dayton compressor. I replaced it years ago when it stopped holding pressure. Now it holds pressure for many days. The 1/4" line goes to the unloader.

 

[metlmunchr]

The check valve leads to the crankcase then comes out of the case and goes to the first stage then to atmosphere.

Could you post a pic of what you describe here? It sounds more like an unloader that allows the pump to come up to speed before it starts to pump rather than a normal discharge check valve which would be piped into the line between the pump discharge and the tank.