Rapidair leakdown rates?

[DocsMachine]

I'm closing in on finishing up a Rapidair/Maxline install in my shop- between the two-bay garage and the small machine room adjacent, I have seven outlets, and the whole thing is a mix of 3/4" and 1/2". Most of the runs are 3/4", with some of the smaller drops (mainly just for blowguns) being the 1/2".

Anyway, it's not by any means complete yet, but today I finished up enough I could pressurize what's up so far. I don't have a proper connection to the compressor, so I just whipped up a couple fittings to make a male-male QD connector, and hooked a hose from the compressor into one of the drop fittings.

I pressurized the whole system, and after a couple snafus, got it up to about 104 PSI on a gauge plugged into another QD outlet. I then shut the valve at the tank to isolate the entire system, hose, gauge and all.

Now, some five hours later, it's down to about 84 PSI. At that rate, the compressor will run roughly three or four times a day just keeping the system charged. My current setup, with just a single hose run straight off the compressor, might run on it's own once a month if I'm not using it.

I'll be hitting the system with some bubbly-water in the morning, but I'm curious what sorts of leakdowns some of you guys might see with similar Rapidair/Maxline systems.

I understand that with all the connections and whatnot that some leakage is inevitable and unavoidable. But having the compressor run multiple times a day just keeping the system charged is not acceptable.

Doc.

 

[topcok88]

I use RapidAir Maxline only. I use a Champion HR5-8, GoodYear whip, and a Milton FIlter/Regulator. I have one ball valve at the tank I close when not actively using the compressed air. I have found that with the compressor off, valve closed, and a blow gun left on my over head mounted hose reel my Filter/Regulator will drop from a system operating pressure of 175 PSIG to maybe 160 PSIG over the course of one month. I do not use my compressed air often but I consider my compressed air system “leak free”. Sounds to me like you have a lot to look over. MaxLine is PEX/AL/PEX and a properly installed fitting/compression ring is pretty robust.


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[MattT]

Now, some five hours later, it's down to about 84 PSI. At that rate, the compressor will run roughly three or four times a day just keeping the system charged.

It's not going to cycle the compressor that much. Your leak(s) has dropped a couple of gallons of pipework 20 psi in 5 hours. Add the tank volume to the system and it'll take way longer to drop enough to fire the compressor.

 

[crook038]

I have around 150 feet of 3/4" rapidair/maxline run in my garage. I can tell you that the rapidair/maxline does not leak. I can also tell you that with 3 hose reels, a 4 post lift with direct air and my air filter/regulator I lose a small amount of volume over several days. I have a ball valve at the compressor that I try to shut off when not working in the garage. I forgot to shut it off the other morning and found when I returned to my garage after about 1 hour, I had a line let go on one of the air/hydraulic jacks for the 4 post lift. I also failed to shut off the air to the lift when I was done with it, I won't do that again. Anyway, if the rapidair/maxline is installed per the instructions, your leaks will generally be from other items in your air system.
Sean

 

[DocsMachine]

Add the tank volume to the system and it'll take way longer to drop enough to fire the compressor.

-Entirely true, I'd forgotten about that.

In any case, this afternoon, some 14 hours after I'd filled and blocked the system, it was down to about 45 PSI. So I went leak-hunting with a spray bottle of Windex.

Of course, it turns out the test gauge coupler itself was one of my biggest leaks.

After that, one of the drain valves had an internal leak (that is, past the ball and seal somehow) and the last was a setup of probably-temporary galvy pipe that's part of a QD port for a bench connection.

All got tightened, and at the moment, it's up to 124 psi again and blocked. Stand by for updates.

On a side note, none of the tubing connections leaked so much as a bubble. All the leaks were at a threaded connection, or in the one drain valve.

Doc.

 

[oldmxracer]

Hope You found all Your leaks !

If You did not ! Purchase a better leak locator, https://www.rectorseal.com/rectorseek-low-temp/

You will be amazed from using Windex or any other product to find the small leaks !

 

[OldNeons]

It sounds like the max line may be more leak resistant? We used rapid air 1/2" in my dads shop with probably 10 drops and he has to shut ball valve off at compressor or it will leak down fairly quickly..... I'll look,into max line for my shop����

 

[DocsMachine]

That depends: Do you have the all-plastic push-to-connect stuff, or are they the actual compression fittings?

The push-to-connect only seals with a single O-ring around the outside of the tube. The compression stuff seals with two O-rings on the inside.

Leakdown update: It's much, much better, but there's still something going on.
As above, yesterday afternoon I pumped it up to 124 psi at about 2:30. By roughly 7 PM, it might have lost half a pound.

But when I looked again at about 10 PM, it was down to about 108. Not sure why it'd do so well for the first almost five hours, but then lose so much more in the following three.

But, I pumped it back up to 117, so we'll see how it is by Sunday afternoon.

Doc.

 

[ybnormal70]

Was there a big temperature difference during the pressure readings? Could be a small part of it.

Kevin

 

[Bretny]

My cheap black iron system can hold pressure for weeks. I would say you have a leak. Time to get the soapy water out.

 

[cspcrx]

My Maxiline seems to hold pressure very well. No leaks and it drops only due to cooling of the air or sitting for several weeks without use.

 

[TurnipTruck]

My 100’ long 3/4” sweated copper and pex circuit has lost half a psi in two weeks, and that may be a temperature change. I have tried to minimize pipe threads (two total), the rest is 20-ish sweat and three sections of pex while traversing five rooms.
In all of my plumbing exploits, I have only had leaks at threaded joints ( except my very first solder joint ever!)

 

[NUTTSGT]

I have a simple black pipe system and I put a ball valve between the compressor and the system. I don't use it everyday so it's not an issue for me to flip the handle and charge up the system.

If something fails while I'm gone, I don't have to worry about the compressor running non-stop either.

 

[sberry]

A valve for that kind of set up is perfect. Turn down a small manifold. In a small garage a valve at tank would be good cheap security. Last reman I did one of the things I did was relocate a little line shut off at the station. My stuff is old. Some of it was on 24/7 and seems as good as it did a while ago but no reason not to use a valve,,, I have forgot it yes,,, but most of the time I reel up in sequence and shut valve off.

 

[DocsMachine]

Quick update: System blocked from the compressor, minimal temperature change throughout the day, it dropped from 117 to 85 PSI in right around 24 hours.

Tonight, I opened it up to the compressor, and it was 114 PSI to start. I'll see how much the whole system loses in a day.

But either way, clearly I've got a nontrivial leak somewhere, and I'm suspecting it might be in one of the plugs on the backs of the wall mount blocks, which I didn't check with the Windex last time. (Seeing as how they're, you know, bolted to the wall. )

Doc.

 

[CJ7VFR]

Quick update: System blocked from the compressor, minimal temperature change throughout the day, it dropped from 117 to 85 PSI in right around 24 hours....

Does that mean you isolated the air compressor from the RapidAir system, and just tested the air tank to see if the tank was leaking?

In my case, I have found that my biggest air leak was coming from the drain valve on the bottom of the air compressor tank. No amount of tightening the wing nut on the drain valve would make it stop. The air compressor tank would leak down from 125 PSI to 50 PSI over night.

I replaced the original drain valve with a better one and now the tank and the whole air system leaks down from 125 PSI to about 100 PSI over night. I am good with that.

As a side note, I also drain my air tank every day to get rid of the condensation that builds up in there, as I don't want rust forming inside the tank. So I don't normally leave the air supply system charged up for more than a day or so.

Jim

 

[DocsMachine]

Latest update:

The system is complete; about 170 total feet of 3/4" MaxLine, and about 35 total feet of 1/2" RapidAir, eight drops with a total of 11 quick-disconnect outlets, two coalescing filters in series, a big 1/2" NPT QD at the compressor (mainly done as a swivel/union rather than as a QD) and a couple of ball valves so the filter block can be isolated.

That's hooked to a 60 gallon single-stage Campbell-Hausfeld, that now has an extended drain made of stainless steel Swagelok industrial instrument tubing.

I ran the system on the 3rd, and let it get up to pressure, then once the cycle stopped, I switched off the power. Once it'd cooled for a couple hours, I simply used a dry-erase pen to mark where the needle was on the gauge face.

Then I basically went on a 10-day vacation.

On the 13th, the pressure for the entire system had dropped 16 psi total, according to the gauge.

That's not bad, all things considered. I may try going over it again with some bubble mix when I have time- I'd like to see 16 psi per month if I could- but it's certainly acceptable at this point.

Doc.