How much leak down to expect?

[jmarkwolf]

I just completed the installation of a new Puma 40-gallon air compressor, 90ft of 3/4in Rapidair Maxline with 5 drops, in my 28ft x 30ft shop. First such installation for me. I always just dragged a hose around where I needed it.

I initially had a big leak in one end of the flexible whip between the compressor and the FRL (filter regulator lubricator), but a tightening of the female end fixed that.

I've still got some leak down (not attributable to the compressor itself), which seems to worsen the more loads that are plugged in (power draw bar on my mill, retractable hose reel, hoses, etc). 40lbs or better over 2 days. I listened near every joint/transition but didn't hear anything.

How much leak down should I expect, or typical?

Is it practical to try to achieve zero leak down?

 

[johninct]

If I understand , you loose 40 psi over 2 days. That is way too much!! You should loose almost nothing over that time.

 

[Sumboodie]

My 80 gallon tank empties after a day or two if I leave the valve open.

I never bothered to fix. Can't hear it leaking.

Have worked in shops with rags wrapped over leaking fittings to quiet it down. Maintenance dept idea of a "fix".

 

[Walkers]

Get a spray bottle of really soapy water and find the leaks. It is possible to achieve zero leaks.

 

[bwringer]

Get a spray bottle of really soapy water and find the leaks. It is possible to achieve zero leaks.

Agreed. There is a leak detector solution used for testing gas connections that is less corrosive than detergent or random shampoo or soap.

I'd grab a bottle of that at the nearest home store, and go leak hunting. You'll find it.

There's no reason to tolerate leaks.

 

[Lucid Moments]

Mine will probably leak out my 60 gallon tank in 3 days or so. I just installed a ball valve almost immediately out of the tank and shut it off there when I leave the shop for more than a few hours.

While I believe a leak free system is possible I don't believe it is worth the effort.

 

[BillK]

My 120 gal leaks down completely over night. A lot is probably coming from the worn out 40 year old compressor but i am sure a lot is also from my 5 or 6 machines that are connected all the time. It has been like that for 30 years and I have never given it another thought. I turn it off every night when I leave and turn it back on in the morning

 

[Jswain]

Lol **** you guys have some big tolerances. I close off my tank and my lines leak ~5-10psi in 24 hours. That's just the lines it would take weeks to drain my 80 gallon tank.

Get out a bottle of soapy water as stated and fix your leaks, if everything leaks it's hard to tell if you get a pinhole or something in your tank/line and that's an indicator I wouldn't want to be without.

With my tank valve closed the tank leaks nothing, or as close to nothing as I can tell. I didn't do anything special with my fittings just thread tape and put out

 

[Sumboodie]

Agreed. There is a leak detector solution used for testing gas connections that is less corrosive than detergent or random shampoo or soap.

I'd grab a bottle of that at the nearest home store, and go leak hunting. You'll find it.

There's no reason to tolerate leaks.

Sure. Sometimes the fix is a PITA or expensive.

 

[mrjaw14]

Mine leaks at a swivel on my hose real. It’s a cheap hose real so I’m not sure I can fix it it I take it apart. My 30 gallon compressor has a female quick connect that I’m sure is leaking too. I use my compressor too frequently to want to take it all apart lol

 

[Doc1976]

Zero leaks here with rapidair system..as said, use a soapy solution at all joints.

 

[Milton Shaw]

I used a motorized ball valve hooked to my lights to turn my shop air off. It leaks down without that valve enough to run overnight. I have most of my pipe behind drywall, 4 hose reels, and 8 drops with couplers, so I cannot fix all the leaks. I found that one of the ultrasonic leak detectors would find just about any leak, but I got that ten years after I closed up my walls with insulation and drywall.

 

[greg13]

First you have to isolate the leak(s), Install a ball valve at the tank and shut it off when you leave for the night. That will tell which side the problem is.
My 80 gal. Erie from 1943 looses about 10psi during the week through the compressor/valves, not enough to mess with.

 

[jmarkwolf]

Update from OP:

I disconnected all loads and pumped up my system to an even 100lbs PSI, and sprayed soapy water on every Rapidair elbow, Tee, manifold/joint at the bottom of each drop, and all the joints along the flexible whip between the air compressor and the filter/regulator, and found.... nothing. No bubbles.

Now I'm wondering if I have a pin leak somewhere along a run of tubing, or if one or more of the cheap Home Depot female universal couplers is leaking.

My plumbing is all clipped to the wall so I suppose it's possible there is a leak on the backside adjacent to the wall, that would be hard to spot.

I saw a Youtube video (link below) of a guy demonstrating and ultrasonic air leak detector that found several leaks in his system, that he swears he could not hear without the detector. The one he used is far more expensive than the typical home garage shop can justify. I'll try to find one to rent.

Saga continues.

 

[Jswain]

If you disconnected all loads and found no leaks do you think maybe one of the things you disconnected was where the leak is? Plug them back in and retest, or leave them unplugged and see if it leaks overnight if not then plug them in one at a time and retest to find the culprit

 

[jmarkwolf]

If you disconnected all loads and found no leaks do you think maybe one of the things you disconnected was where the leak is? Plug them back in and retest, or leave them unplugged and see if it leaks overnight if not then plug them in one at a time and retest to find the culprit

I wasn't clear. I found no leaks with the soap bubbles, but the air pressure bled off rapidly. And the air pressure, as indicated at the compressor, will leak down 65lbs over night, from 100lbs.

 

[Jswain]

Did you check the drain on the bottom of the compressor? Sometimes the bubbles from smaller leaks will take a minute to get your attention

 

[toyotadriver]

Mine will drop 20-40 psi in 3-4 days. It's likely leaking at the filter and at the three connected hose reels. It's not enough for me to worry about.

 

[vanapplebomb]

Sounds like a lot of you have some pretty bad leaks.

I have 85’ of 3/4 maxline in my shop, regulated to 120 psi, with four air drops. Each drop has a manifold with three outlets. If I shut the supply air off at the tank, the pressure remaining in the line will loose about 5 psi per week. After comming back from a two week vacation, the line was only down to 110psi.

for those who actually notice the compressor pressure dropping off over the course of a day, that needs attention in my book. Either it is the air line or the compressor itself. I would immediately be suspect of something if I noticed the gauge of my 80 gallon tank dropped more than 5psi over night (10psi max if it was running continuously, aka, a very hot air tank) ...which is just due to air cooling after shut down. I wouldn’t want a compressor to leak down more than 5-10psi per week.

 

[Packard V8]

FWIW, I was servicing an IR 5hp compressor and noticed it leaked down immediately. Checking with soapy water spray, the leak is where the manifold threads into the top of the tank. There is a layer of goop there, indicating an previous attempt at stopping the leak. After examination, it appears the design of the manifold casting is such the bottom threads tight against the top of the tank and even after disassembly and cleaning, there may not be enough thread to allow another 360 turn.

jack vines

 

[dogdog]

I wasn't clear. I found no leaks with the soap bubbles, but the air pressure bled off rapidly. And the air pressure, as indicated at the compressor, will leak down 65lbs over night, from 100lbs.

Not that big compressor, but I do believe it's the same. When my craftsman 33 gallon was acting like that .. Just leaks down the whole tank over night . There was no apparent leaks from any joints / connectors on the outside connectors/switches/ safety pop off etc. I was able to later trace it down to the check valve corroded/pitted or just that film of green stuff was able to prevent it from seating shut, leaking back into the pump over night.

In my case I cleaned the valve by dunking it in ultra sonic solution and let it run, and clean scrub with royal purple etc. Its fixed now holding pressure for a few weeks... at least it wasn't leaked down over night.

maybe check there. maybe right at the pipe with your automotive stethoscope.

 

[oldwino]

Guess I’m real lucky. Running a small twin tank Hatachi compressor with an 11 gallon secondary tank plumbed in. I can go 4-5 days and its still harder than a whores heart

 

[Doc1976]

Don't you have a ball valve between tank and whip at the regulator? I assume that's how you plumbed it. I always shut off the ball valve on my system at the end if the day. This way if you do get a leak, it will only drain the plumbed lines and not the compressor tank. I went overboard on mine, 3 ball valves. One at the tank, one just before the maxaire plumbing, and one to the other coupler for a long hose(kind of a T setup after filter and regulator. Main reason for this was for future servicing without draining the whole system, also I can have different areas of the shop on or off to suit my needs. Like I said, overkill but it works good for me.

 

[jmarkwolf]

Don't you have a ball valve between tank and whip at the regulator? I assume that's how you plumbed it. I always shut off the ball valve on my system at the end if the day. This way if you do get a leak, it will only drain the plumbed lines and not the compressor tank.

OP here:

Yes, I do have a ball valve at the compressor tank before the filter/regulator, but that won't change the fact that while using air tools, the compressor will cycle more often than necessary due to the leak(s).

I discovered some ultrasonic leak detector apps for Smart Phones. May try another round of soap bubbles, then try the phone apps.

 

[American Locomotive]

If you think the female disconnects are leaking - just try filling a cup with water and submerging the whole quick connect in water. If it's leaking, it should be quite apparent. Just make sure you blow it out afterwards.

 

[vanapplebomb]

Guess I’m real lucky. Running a small twin tank Hatachi compressor with an 11 gallon secondary tank plumbed in. I can go 4-5 days and its still harder than a whores heart

And that’s how it should be.

Proper threaded joints, ball valves, and compressor check valves shouldn’t leak down over the course of a work week.

 

[bluesboy]

I used a motorized ball valve hooked to my lights to turn my shop air off. It leaks down without that valve enough to run overnight. I have most of my pipe behind drywall, 4 hose reels, and 8 drops with couplers, so I cannot fix all the leaks. I found that one of the ultrasonic leak detectors would find just about any leak, but I got that ten years after I closed up my walls with insulation and drywall.

 

[bluesboy]

Would like to see pics of motorized ball valve

 

[Doc1976]

OP here:

Yes, I do have a ball valve at the compressor tank before the filter/regulator, but that won't change the fact that while using air tools, the compressor will cycle more often than necessary due to the leak(s).

I discovered some ultrasonic leak detector apps for Smart Phones. May try another round of soap bubbles, then try the phone apps.

Sorry, I thought the concern was that it was leaking down overnight while not in use.

 

[lpakiz]

I also use a motorized ball valve.
Search Ebay for them. A 3/4” Stainless Steel model might be $40-60.
I have a 110 volt, 2 wire, Normally Closed, that I plug into a Wion brand Smart outlet (Menards $20)
The valve is plumbed in right after the pressure tank.
Since I have a branch line buried underground to supply my basement, and my house wifi reaches the shop, I can turn it on and off from my iphone. The Wion also has a manual switch right on the device, so it can be turned on locally, without your phone.

 

[csp]

Yes, I do have a ball valve at the compressor tank before the filter/regulator, but that won't change the fact that while using air tools, the compressor will cycle more often than necessary due to the leak(s).

If you don't have air leaks at non-quick connect fittings when air tools aren't in use, the same fittings aren't going to suddenly spring a leak just because a tool is connected.

You either have a leak where your tool is connected or have an errant expectation of air use by said tools.

I was also under the impression that you were losing pressure overnight with nothing connected to the lines. You shouldn't be leaving tools on the quick connects overnight if that's the case. Another way to isolate the leak is to close the ball valve at the tank exit and see if it still drops overnight. Process of elimination....

 

[dr_clyde]

I didn’t build the pipe system in my shop, and there are quite a few leaks. It’ll lose 40-60psi overnight

My landlord and I share an air system. We both have 10hp screw compressors, and the whole building is plumbed together. 16k square feet. Whoever comes in first in the morning turns on the compressor for the day. The building is all on one electric meter, so it doesn’t really matter who’s compressor is running.

We each have pretty good size receivers, so there’s a lot of air in the system.

The joy of a screw compressor is that even from dead empty, my compressor will build up to working pressure in just a few minutes. So a leak really doesn’t matter all that much. The CNC machines use enough air that one extra cycle to fill up in the morning isn’t a big deal.

 

[jmarkwolf]

OP here with some clarification:

My system will leak down 10's of pounds overnight when the compressor is run up to 100lbs then shut off, and the shutoff valve at the compressor is open, with no tools nor hoses attached to any couplers anywhere in the system.

The compressor alone will leak also with the shutoff valve closed but only slowly (10's of pounds per week). Not sure where this leak is but plan to investigate with an ultrasonic leak detector app available for Smart Phones.

 

[Supa Dexta]

Have you actually left it a week to observe that, or did it drop 5-10 lbs over night, and you just assumed it would do that every night after?

because if only a single night was observed, thats just the hot air in the tank cooling, and will remain at that pressure after that.

 

[csp]

My system will leak down 10's of pounds overnight when the compressor is run up to 100lbs then shut off, and the shutoff valve at the compressor is open, with no tools nor hoses attached to any couplers anywhere in the system.

The couplers could still be the leaking culprits. With as much air as you're losing overnight there shouldn't be any need for anything outside of soapy water to find it.

 

[klassenl]

I used pex pipe to run my air lines and I have no leaks in the line. My cheap quick connects are a different matter

 

[jmarkwolf]

Have you actually left it a week to observe that, or did it drop 5-10 lbs over night, and you just assumed it would do that every night after?

because if only a single night was observed, thats just the hot air in the tank cooling, and will remain at that pressure after that.

OP here:

The compressor leaked 40lbs over the course of a week with the shut-off at the compressor valve closed.

The couplers could still be the leaking culprits. With as much air as you're losing overnight there shouldn't be any need for anything outside of soapy water to find it.

Agreement here, but I've been unsuccessful so far (1 attempt with a spray bottle). Will try again with a brush, as time allows. The manifolds at the bottom of each drop has a pipe plug on the back side (against the wall) which may also be contributing.