# Bad Check Valve?



## Dubs89 (Apr 21, 2011)

Hey all, just wondering if anyone here has experienced a bad check valve in their air system?
I actually just had a bad check valve go bad on me and it actually resulted in a couple of blown fuses  because at that point I couldn't figure out why this was happening to me.

Also, because I am new to my air set up... I did some research before purchasing it (like a smarty pants) and had noticed a 480c compressor fills up a 5 gal. tanks rather quickly.... well I can now say that with a bad check valve it made a world of a difference. Prior to discovering the bad valve it would take like a good 30 mins to fill up my tank then bags... but now it's like what it's supposed to be... 5 mins? haha

Just curious as to anyone having problems with existing check valves. 

Cheers fellas :wave:


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## Slamtastic (Jul 24, 2010)

Well I've never heard of a check valve being so bad that it takes forever to fill the tank. If you just leave it filled how long does it take to leak out?

A way to test the check valve is to take off the leader line (BEFORE THE CHECK VALVE) and see if air is back flowing.

Also check your inlet to see if it's plugged with anything because it shouldn't be taking that long to fill.


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## [email protected] (Feb 19, 2010)

Viair seemed to have a bad batch of check valves on 400s and 380s last year, we saw an unusually high number of failures around spring time. When they failed they weren't allowing any air through before the glue heated up enough for the crimps to pop off the ends.. Generally they tend to hold up pretty well except in the extreme cold. If you're in a really cold climate, the SMCs are the ones to go for.


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## Dubs89 (Apr 21, 2011)

dubbin18 said:


> Well I've never heard of a check valve being so bad that it takes forever to fill the tank. If you just leave it filled how long does it take to leak out?
> 
> A way to test the check valve is to take off the leader line (BEFORE THE CHECK VALVE) and see if air is back flowing.
> 
> Also check your inlet to see if it's plugged with anything because it shouldn't be taking that long to fill.


Yeah, It was worth a shot to take apart the leader line before the check valve.... although I am new to the air set up and I'm not that much of an idiot to know that something is wrong with the time it takes to fill... haha But yeah, it actually does escape through the check valve as well. I can fill it up to 150psi and leave it and the next day it will be gone.. haha


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## Dubs89 (Apr 21, 2011)

[email protected] said:


> Viair seemed to have a bad batch of check valves on 400s and 380s last year, we saw an unusually high number of failures around spring time. When they failed they weren't allowing any air through before the glue heated up enough for the crimps to pop off the ends.. Generally they tend to hold up pretty well except in the extreme cold. If you're in a really cold climate, the SMCs are the ones to go for.


Yeah It would maybe take about 20 mins to fill 80psi haha from zero.... so I'm glad I got that figured out because a check valve isn't something you normally look for that is causing a blown fuse and leak. 

Also, I do live in NH and it can get a little chilly here and I do have SMC water-trap. seems to be holding well.


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## reynolds9000 (Oct 16, 2003)

I just installed an NK2000 SMC check valve to replace my faulty ViAir one. I have a 400c compressor so there is definitely truth to what Will is saying about the valves on 380 and 400c's.


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## _Dirty_ (Sep 30, 2009)

Dubs89 said:


> Yeah It would maybe take about 20 mins to fill 80psi haha from zero....


Dannng. I get pissed when it takes 45sec from 110-145psi


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## Dubs89 (Apr 21, 2011)

yeah dude im so happy about the time it now takes rather then before. haha I sucked when you had to leave your house earlier to just go out with some friends. haha :beer:


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## tgidave (May 14, 2008)

viair checks that come with the stock lines go pretty often. they run into the issue where the valve gets stuck open. 

the smc ones are very good.


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## chadone (Apr 26, 2010)

I don't even have check valves in my set up. Are they necessary? Running duel viair 400s


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## Slamtastic (Jul 24, 2010)

chadone said:


> I don't even have check valves in my set up. Are they necessary? Running duel viair 400s


Yes you do and yes they are.

It's on the end of the leader line.

If you didn't have them the air would instantly leak out.


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## chadone (Apr 26, 2010)

Oh in the braided line of the compressor or the manifold?


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## Slamtastic (Jul 24, 2010)

chadone said:


> Oh in the braided line of the compressor or the manifold?


At the end of the braided line on the comoressor. There might br a label that says 'check valve'.


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## msheehan (Jan 28, 2011)

is a check valve really necessary in an air set up? i work in oil plants and they use check valves to prevent explosions, but an air system should not explode?


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## Slamtastic (Jul 24, 2010)

msheehan said:


> is a check valve really necessary in an air set up? i work in oil plants and they use check valves to prevent explosions, but an air system should not explode?


Check valves prevent backflow. The air you just pumped into the tank will leak back through the compressor.


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## Dubs89 (Apr 21, 2011)

dubbin18 said:


> Check valves prevent backflow. The air you just pumped into the tank will leak back through the compressor.


I actually did notice this while trying to figure out the issue... I'm glad to have been figuring this out now, rather than later


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## ering2010 (Aug 19, 2007)

is it suggested to use smc check valves even though the compressors have check valves? How often do the viair check valves go out?


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## Dubs89 (Apr 21, 2011)

Good question... I'm not sure haha


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