# What is an acceptable tank pressure loss rate?



## cmdshft (Oct 17, 2011)

I've made sure that all my fittings are snug. I've had it installed by someone that does bus air systems for a living and I even put an SMC check valve on the leader line of the compressor.

I am still seeing a drop in tank pressure (bags do not drop in pressure) at a fairly quick rate to me, about 5psi in 1 hour. Is that an acceptable amount to lose? I've checked the compressor for leaks with the finger over the port, and there's no audible/palpable leak. Sprayed all the fittings with soapy water, no bubbles form. I did tighten up all the fittings which reduced the leak from 5psi in about 5 minutes to the 1 hour rate. But it still seems to be leaking somewhere, not sure where.

Any ideas?


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## PassatSport15 (Sep 11, 2016)

cmdshft said:


> I've made sure that all my fittings are snug. I've had it installed by someone that does bus air systems for a living and I even put an SMC check valve on the leader line of the compressor.
> 
> I am still seeing a drop in tank pressure (bags do not drop in pressure) at a fairly quick rate to me, about 5psi in 1 hour. Is that an acceptable amount to lose? I've checked the compressor for leaks with the finger over the port, and there's no audible/palpable leak. Sprayed all the fittings with soapy water, no bubbles form. I did tighten up all the fittings which reduced the leak from 5psi in about 5 minutes to the 1 hour rate. But it still seems to be leaking somewhere, not sure where.
> 
> Any ideas?


That's bad..

Get a bottle put little of dishwashing soap & water. Spray every line. Always good to have a pressure gauge on the tank, analog one.


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## Teh_Chris (Dec 31, 2007)

Me personally. Zero is acceptable. Hence why i bailed on PTC fittings and use swagelok and hardlines


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## Teh_Chris (Dec 31, 2007)

2x on the soapy water spray bottles. Huuuge help in finding leaks


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## cmdshft (Oct 17, 2011)

PassatSport15 said:


> That's bad..
> 
> Get a bottle put little of dishwashing soap & water. Spray every line. Always good to have a pressure gauge on the tank, analog one.


I've done that several times... Zero bubbles form on any of the fittings. I'm strongly considering putting one on.



Teh_Chris said:


> Me personally. Zero is acceptable. Hence why i bailed on PTC fittings and use swagelok and hardlines


I'd love to do hardlines but that's for the future. I'm going to look into the swagelok bits, heard they were a tad pricey.


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## Teh_Chris (Dec 31, 2007)

cmdshft said:


> I've done that several times... Zero bubbles form on any of the fittings. I'm strongly considering putting one on.
> 
> 
> 
> I'd love to do hardlines but that's for the future. I'm going to look into the swagelok bits, heard they were a tad pricey.


They are pricey but if installed correctly will not leak and are rated at alooooot higher than the 150ish psi ull be running










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## cmdshft (Oct 17, 2011)

Very cool.

So actually, you mention 150psi-ish. I've been pumping my 200psi rated aluminum tank to 175psi, so maybe the pressure is too high for the ptc fittings? I assumed that since the tank can hold 200psi, 175psi would be okay but if the fittings can't hold more than 150psi then I think that's my issue.


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## cmdshft (Oct 17, 2011)

I lowered the tank max psi setting to 150psi and it's still very slowly losing pressure.

I'm wondering if it's the filter between the tank and manifold. If it's not working properly, could it be leaking despite all the other fittings seemingly not leaking?

Would it be better to run a 1/4" trap on the comp leader instead or do I need to have the filter still on the tank-manifold line?

EDIT: I'm sitting in the car right now, I'm completely aired out and I noticed that then front-right bag now has 1psi in it and the front-left has started to fluctuate between 0 and 1psi. As of this edit, the left front has stayed at 1psi. I do hear occasional pops coming from where the manifold is mounted. I'm starting to suspect an issue with the manifold...


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## PassatSport15 (Sep 11, 2016)

Teh_Chris said:


> 2x on the soapy water spray bottles. Huuuge help in finding leaks
> 
> 
> Sent from my iPhone using Tapatalk


Yes sir, makes things a whole lot easier!


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## PassatSport15 (Sep 11, 2016)

What setup up you have?

Have you checked every single fitting or connections with the soap & water method.?

It could be your compressor as well. You can check by putting a ballon into the airfilter side. Just take out that filter out and put a ballon in place of that. 

Let's start over! If we can't pinpoint the issue. 

Give us description of what you have setup wise..

Pics will help as well..


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## cmdshft (Oct 17, 2011)

I'm using Airlift 3P system, 5gal aluminum tank, Viair 444c comp with 1/4" leader and 1/4" SMC check valve into 1/4"-3/8" bung, 1/4" drain port with petcock valve and tire valve with SMC PTC fittings, 1/4" water trap on the tank to manifold line, 1/4" air lines. Manifold is mounted level and above the tank in the CD-changer cubby (MK4 GTI).

I've sprayed every single fitting with soap and water. Not one single bubble shows up.

I did not use the balloon trick on the comp.

I watched the two front bags gain 1psi sitting for almost an hour. There is a slight occasional pop from the manifold location, not regular or consistent.

I will take pics of the setup and post them tomorrow.


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## Teh_Chris (Dec 31, 2007)

Check the manifold too 


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## Teh_Chris (Dec 31, 2007)

And we are talking tank pressure (Yellow) not bag pressure (Red) drops right ... sry i drove my Rgli today not my Tiguan(3P) so v2 display will have to work










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## northendroid (Sep 16, 2014)

cmdshft said:


> I'm wondering if it's the filter between the tank and manifold. If it's not working properly, could it be leaking despite all the other fittings seemingly not leaking?


So have you check the schrader valve on the bottom of the water trap and the bowl "O" ring for leaks? Is this a new installation or an existing one and the leak has just started to occur? The only other thing I can think of is to remove the air tank plug the port and pressurize the tank then leak test all of the welded joints. With the tank tested you know it's in the plumbing/fittings. As for the ballon test not a bad idea to make sure it's not the check but with loosing 10 psi in 5 minute you'd felt/heard some pressure when you removed your finger from the port. Did you hold your finger over the port for 5 minutes?

Can you take of picture of your setup, tank lines to tank, water trap etc. and post.


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## Teh_Chris (Dec 31, 2007)

Possibly the check valve letting it bleed back thru the compressor... the airlift ones fail more often than an smc one will so thats another possible leak


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## PassatSport15 (Sep 11, 2016)

If ur losing at much pressure. U definitely could feel it. Especially if it's on the ann it's
Elf.


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## PassatSport15 (Sep 11, 2016)

cmdshft said:


> I've made sure that all my fittings are snug. I've had it installed by someone that does bus air systems for a living and I even put an SMC check valve on the leader line of the compressor.
> 
> I am still seeing a drop in tank pressure (bags do not drop in pressure) at a fairly quick rate to me, about 5psi in 1 hour. Is that an acceptable amount to lose? I've checked the compressor for leaks with the finger over the port, and there's no audible/palpable leak. Sprayed all the fittings with soapy water, no bubbles form. I did tighten up all the fittings which reduced the leak from 5psi in about 5 minutes to the 1 hour rate. But it still seems to be leaking somewhere, not sure where.
> 
> Any ideas?


Pm ur address, I live 15 min away from you. If you want help or another hand.


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## cmdshft (Oct 17, 2011)

Hey thanks for the replies guys.

I am talking about tank pressure dropping, bag's don't seem to be losing air at all.

I put an SMC check valve on the comp.

I did not check the Schrader valve on the end of the drain line. 

I'm currently at a friend's house that also has an air suspension done so we're gonna double check the system.

Overnight I went from 150psi to 90psi in the tank. None of that went into the bags.

I'll send you a PM.


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## cmdshft (Oct 17, 2011)

Well after constant spraying, I (by mistake) sprayed the water trap body itself... And it started bubbling immediately. So, I now know where my leak is. At least I know all my fittings are air tight...

Going to try and see if AirLift will warranty the trap since it's new and was never opened.


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## PassatSport15 (Sep 11, 2016)

cmdshft said:


> Well after constant spraying, I (by mistake) sprayed the water trap body itself... And it started bubbling immediately. So, I now know where my leak is. At least I know all my fittings are air tight...
> 
> Going to try and see if AirLift will warranty the trap since it's new and was never opened.


Glad, you got it all sorted out..

Airlift is great on warranty stuff. They don't ask for receipts, at least with the small issues, that I had. 

See if their is an upgrade..

I know their like 30 bucks from bagriders SMC


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## northendroid (Sep 16, 2014)

cmdshft said:


> Well after constant spraying, I (by mistake) sprayed the water trap body itself... And it started bubbling immediately. So, I now know where my leak is. At least I know all my fittings are air tight...
> 
> Going to try and see if AirLift will warranty the trap since it's new and was never opened.


Glad you found it I know it can get frustrating but not giving up is the key!


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## Teh_Chris (Dec 31, 2007)

cmdshft said:


> Well after constant spraying, I (by mistake) sprayed the water trap body itself... And it started bubbling immediately. So, I now know where my leak is. At least I know all my fittings are air tight...
> 
> Going to try and see if AirLift will warranty the trap since it's new and was never opened.


If they wont i have 2 or 3 of them since i went straight out the box with SMCs on my tig and jetta. 


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## Piso (Jan 4, 2012)

I had a slow leak coming from the bottom of my water trap. What I did was mounting it before my smc check valve. No more leaks and I can still empty it with the pressure left in my compressor leader line


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## cmdshft (Oct 17, 2011)

Good news is AirLift is sending me a replacement water trap under warranty.


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## PassatSport15 (Sep 11, 2016)

Nice!


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## northendroid (Sep 16, 2014)

cmdshft said:


> Good news is AirLift is sending me a replacement water trap under warranty.


:thumbup:


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## Teh_Chris (Dec 31, 2007)

cmdshft said:


> Good news is AirLift is sending me a replacement water trap under warranty.


Hells yes sir


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## cmdshft (Oct 17, 2011)

I received and installed my new AirLift water trap and so far it's holding pressure just fine. I wanted the tank to hold 175psi so I set it to 180psi due to thermal expansion/laws of physics so the air will cool down and be at the pressure I want.

It's been holding for the past hour at exactly 175psi.

Much kudos to AirLift for being a super awesome company!


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## Teh_Chris (Dec 31, 2007)

cmdshft said:


> I received and installed my new AirLift water trap and so far it's holding pressure just fine. I wanted the tank to hold 175psi so I set it to 180psi due to thermal expansion/laws of physics so the air will cool down and be at the pressure I want.
> 
> It's been holding for the past hour at exactly 175psi.
> 
> Much kudos to AirLift for being a super awesome company!


Very nice  


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