Hi all -

I just finished installing a Viair on-board compressor & tank (Viair 10007 kit) and spent the last couple of days chasing down leaks.

The Viair install manual says, "Do not over tighten if your port fittings are made from brass, since brass threads can be stripped." Of course, all the fittings they supplied are brass so, I was careful not to "over tighten". Well, that was for the birds; I had to go back to each one and re-apply sealant and tighten the **** out of them.

So, now I don't have a bunch of obvious leaks (no bubbles from the soapy spray water) but, the tank still loses pressure slowly - like 150lbs down to 100lbs in an hour or so.

To any of you who have on-board compressors & tanks, what is the typical length of time your fully charged tank will hold most of its pressure? How often does your compressor have to run to maintain workable pressure - ( not operating air tools, inflating tires, etc. ).

Thanx.

 

You said you applied a sealant on the threads. What are you using?

 

It should maintain pressure indefinitely if you are not using it.

 

Well, not really. There will always be a little loss.
150 to 100 over an hour seems excessive.

Dont forget, you shouldnt be leaving the tank pressurized for long periods of time anyway. A valve should be installed at the lowest point in the tank and drained periodically; and personally, I dont like leaving a tank pressurized when not in use.

 

Oh yes, really. Not one molecule of air should leak out if nothing is using it. I just dug out a pancake compressor I have, that I haven't used in over a year. Still has exactly 120PSI in it, right where it shut off last time. It is common for air systems to leak, and it's not really a problem unless it bothers you. It's up to you what is acceptable.

There is nothing wrong with leaving the tank pressurized. It does need to have the moisture drained on a regular basis, but after that, it makes no difference if it has pressure or not.

 

Its not the tank that leaks, its the hoses. Over time they will leak.
And I have seen a lot of manufacturers recommend draining tanks when not in use. I presume its a safety thing.

 

Over months and months. Day to day you shouldn't notice any drop. Just like tires.

More likely a lawyer thing. There is nothing unsafe about leaving a tank pressurized. It's also just like tires, you wouldn't let the air out of them when you aren't using them right? Air tanks are very similar to propane tanks, which obviously are always under pressure without problems.

 

So which is it? You are contradicting yourself. I said 150 to 100 over an hour is too much, but that eventually air will leak. I was not wrong. So please.. Stop.

Unless there is a fire. Then its a big bomb. If a tank is in storage, it is wise to let the air out, if not for you, do it for the firemen.

You are arguing a moot point.

 

By "eventually" you did not mean months. From day to day you should not notice any air loss. Not even week to week.

I'm sorry but that is ridiculous. By the same thinking you shouldn't store anything that comes in a pressurized can. What about your gas tank? You don't think that's more dangerous than the air tank? In the event of a fire the pressure relief valve would open and safely let the air out. Or the air lines would melt and do the same. It would not explode.

There is zero reason to let the air out of your tank. You are just adding a bunch of extra wear to your compressor if you have to charge it every time you want you use it.

 

You cant say what I did or did not mean.

I really dont want to argue this, but you are not making equal comparisons.
A pressurized can doesnt have the same potential energy as a 2 gallon tank (or in your home even more), and fuel tanks are plastic so you dont have metal shrapnel in the event of an explosion.

I'm not advocating draining the tank every time you park, like I said earlier, "when storing a tank."
As far as "not exploding" I have personally seen pressurized tanks explode in vehicles on fire.

From a random owners manual from Ingersoll Rand on air compressors:

"...Drain tank daily or after each use..."

Anyway, enough senseless bickering, back to the OP's question.

 

Then it was not installed correctly with a safety relief valve. Air tanks are absolutely not a fire safety issue. Ask a fireman.

Should I go empty the propane tank on my BBQ in case there is a fire? I probably won't use it again until spring.

 

Lol I love new forum members...
I would ask one but I dont really want to wake Dad up, and I dont go back to work to ask the guys at the station until late tonight.

OP... By now you have probably gathered that you are loosing too much air. Viair recommends Loctite 545 on the threads as a sealant. You have done the soap and water test, but I would say do it again. Do you have any quick connect fittings that could be leaking?

 

mine will hold air for at least 5 days before leaking enough to make the compressor come on. and i know where my leak is, the quick connect is bad.

 

I'm using Permatex 80632 Thread Sealant with PTFE (same as 80631 but in a 4 oz can see Thread Sealants : Permatex® Thread Sealant with PTFE ).

The Viair website FAQs recommends Loctite 545 as a thread sealant but, I couldn't find it anywhere; the Permatex sealant was available at Advance Auto.

I spent some more time on the fittings after my initial message and found that the reducer fitting used to install the pressure relay wouldn't seal after a couple of attempts at reapplying sealant and re tightening. So, I finally used some PTFE tape (aka "teflon tape") on the fitting and that seems to have worked.

I read that using the tape is not recommended because it can shred and produce small slivers and threads that can foul pressure switches and gauges - but, I wasn't getting anywhere with the liquid sealant so, I guess I'll just have to live with it.

I'm still getting a slow leak - now, 150lb to 100lb in about 3-4 hours. I can understand that there may be small leaks (and even some back leakage through the compressor) but, I didn't know was typical for this Viair system (compressor # 450C with 2.5 gal tank).

I appreciate everybody's comments and feedback.

 

It's possible you cracked one of the fittings if you tightened it too much, but I agree, they need to be really tight. I've seen quite a few crack. Also, if you're not seeing any bubbles, it could be a bad check valve leaking out through the compressor. I'd probably take it all apart, clean/check all the fittings, and try again. I prefer the thread tape for this kind of stuff, it's thicker, better with china made threads.

Are there any air lines held on with hose clamps? If so they usually leak.