Air compressor piping question

[lml999]

I had copper pipe run from an air compressor in my utility room to a drop in my workshop and a second in my garage, about 50 feet total. I've got five quick disconnect fittings, all connected with teflon tape in the joints, and two half turn drain fittings in the system.

So here's the question...how long should I expect for the system to maintain pressure after I turn off the compressor? 10 minutes, an hour, days?

I think the system goes from 150 to 40 lbs in about an hour.

I don't hear any obvious source of air leakage. Is this an expected drainage rate for my configuration, or do I have a leak, loose fitting, or bad connector somewhere? What's the best way to find a leak?

Thanks!

 

[greg13]

The easiest way to find leaks is a soap & water mix, spray it on and look for bubbles. In theory, the system should hold pressure for ever if there are no leaks. I would put a ball valve at the tank and shut the lines off when not in use to keep the tank full.
If the pressure still drops off in the tank there may be valve leakage in the compressor.

 

[Highbeam]

I had copper pipe run from an air compressor in my utility room to a drop in my workshop and a second in my garage, about 50 feet total. I've got five quick disconnect fittings, all connected with teflon tape in the joints, and two half turn drain fittings in the system.

So here's the question...how long should I expect for the system to maintain pressure after I turn off the compressor? 10 minutes, an hour, days?

I think the system goes from 150 to 40 lbs in about an hour.

I don't hear any obvious source of air leakage. Is this an expected drainage rate for my configuration, or do I have a leak, loose fitting, or bad connector somewhere? What's the best way to find a leak?

Thanks!

You have a big leak. Can you isolate the compressor? Normally there is a valve at the tank.

As the tank cools you will lose some pressure but not all of it.

 

[RobbieB]

I would suspect the QD's first.

 

[lml999]

Thanks for the suggestions. If I only use the tank intermittently (could be weeks or more between uses), is it better to leave it pressurized or unpressurized?

 

[greg13]

I keep mine full all the time (unless I forget to shut the valve off) , that way you don't have to wait for it to come up to pressure. The compressor is a 30 yr old craftsman and the only thing I have had to change is the pressure switch.