air compressor leak

[rdsk8ter]

First off if this is in the wrong section I appoligize. Ok I am going nuts I have a couple leaks in my air compressor system in my garage. The compressor has a shutoff befor it goes to the shop. The compressor leaks down about 40 psi overnight. I have pulled apart all the fittings on the tank. I have re-taped them and screwed them back in. All I can think here is that device that reads the pressure and kicks on power and off. Could this possible loose psi? Also the second system has 3-20 gallon tanks the pressure regulator and water traps. This part of the system looses right about 20 psi overnight (I can live with this). And the main system looses about the same 20 psi. All three "zones" can be shut off independently of the rest. I guess what Im looking for is any new ideas to find the leaks. The whole system has about 120' 3/4 copper(main feed tubes), 80' 1/2 copper(down pipes and drain tubes to remove water from tanks in attic), 2 water traps(1 pipe t's into both then they both t back into one pipe. I was having trouble with the one keeping up.), there are about 15 quick connects, and a hose reel, there are 3-20 gallon tanks and a 80 gallon tank(on the compressor). Any Ideas on what could be leaking All of the connects are after the main shutoff. Thanks alot guys

[gwnwar]

Do you have teflon tape on all threads/connectors.. Seeing you have copper pipe is it all sodered together?? Have you tryed checking each connector with soapy water mix for leaks. Have you shut off each zone to isolate leaks.. Quick disconnects leak with use. Are the hoses hard lined to the tubing or quick connect.. Have you checked the working end of the hoses connector for leaks and the hose for a leak. Have fun

[WizardBlack]

The compressor itself has spots where it can leak, too.

[rdsk8ter]

found a good idea on another forum I took a funnel and put it in my ear and found one sizeable leak at the tank now it dropped under 15 psi all night. the system I found my pressure regulator is leaking a little as well as the water traps I pulled the traps apart cleaned them up siliconed the drain tubes and now it only lostabout 10 psi the funnel trick works well just time consuming

[rdsk8ter]

Do you have teflon tape on all threads/connectors.. Seeing you have copper pipe is it all sodered together?? Have you tryed checking each connector with soapy water mix for leaks. Have you shut off each zone to isolate leaks.. Quick disconnects leak with use. Are the hoses hard lined to the tubing or quick connect.. Have you checked the working end of the hoses connector for leaks and the hose for a leak. Have fun

It is all sodered. I tried the soapy water might try again though. Each zone was shut off from the next to isolate the leak. there are no hoses hardlined or connected to the quick connects. Is it possible for a quick connect to leak when nothing is plugged into it? I pulled one apart re taped it twice and its still leaking should i replace it or?

[Tony D]

For leaks, use "SNOOP" sold though Swagelock distributors. It's MUCH better than dishwashing soap. It even suprised me how one would not show a leak and another would.

 

I'd ask if you are aftercooled from your compressor, and are you using high volumes before you shut down for the evening. If you are running the compressor a lot, the tank and air inside will heat up---especially if you don't have a good aftercooler. The resultant cooling overnight will cause a big drop in an 80 gallon tank. 20 psi would not be uncommon. From your water problems it sounds like you don't have a cooler.

 

Do you have an auto-drain on the tank? If it's releasing condensate overnight, it can also bleed it down.

 

The isolation valve should be a ball valve ideally, they have less incidence of leakage than cheap gate valves usually found in that service.

 

Do you have an EXTERNAL check valve on your line from the aftercooler to the tank? It's redundant, but this will help when the compressor's valves are leaking down.

 

For compressor valve check, take some good duct-tape and remove your air cleaner. Paste the tape over the hole where your air cleaner was, and observe. If it puffs up (and it should do it relatively quicikly) then you have some leakage on the valve system in your compressor.

 

Adding an external check valve rated for the discharge temperature will stop this, and depending on how big your compressor discharge line is, could be as little as $15. Which will be cheaper than overhauling your valves.

 

Just beware that if it is valves, they will only get worse, if you don't put an external check valve (Conbraco Ball-Style Check Valve or a Whitey/Nupro poppet style) in the system, eventually the valves will leak tank pressure into the compression chamber while running, elevating the discharge tempreature. This can lead to temperatures in excess of 451F, and lighting cigarettes off your discharge pipe...

 

But I digress....

 

YES, a quick-connect can most DEFINATELY leak with nothing on it, and that is one of the points you should SNOOP with the detector. They are cheap, if they are leaking, replace them. Consider "THOR" style connectors for main line connections, with the lighter duty "AMFLO" CP Style for point of use hoses, air tools etc...

 

My battery is dying, if you want more info---PM me. I do air compressors for a living. In Morocco now on a startup of a couple of 'baby' units. 888KW each...

 

Yep, these are 'babies' compared to some of the stuff I've worked on...but I have done/can do everything from fractional to multi-thousand horsepower systems.