I have a 480c hooked to a 3gl tank. Everything put together with 545. It use to be in my toolbox. Had zero leaks would hold 200psi for days. Resently moved it under the truck on the frame. Then I started getting a slow leak loosing about 50psi overnight. So the OCD dude I am I redid every fitting, checked for leaks and found none. Still loose about 50psi a day, annoying because now the compressor has to fill the tank every morning.
Ok, so here’s the weird part. If I disconnect the compressor from the tank leaving the check valve on. it will hold 200psi for days, but with the leader hose hooked up I loose 50psi a day. I figured weak check valve so I got a a new industrial check valve. still have the same problem.
Its almost like the compressor holds enough pressure in the leader hose the just keep the check valve open slightly. Anyone hear of this?? Driving me nuts for 2 weeks.
You’re right, that is very weird and it sounds like the compressor is affecting it somehow. Check valves can be torque sensitive so I was wondering if that was specified in the instructions but having the same symptoms with 2 different valves kind of defeats that theory.
yea… I made sure not to over tighten the CV. Learned that the hard way a while back with the Viair valves. The valve seals 100% with no leader attached (like in the pic) Will stay at 200 all week. The only thing I have different than before is the compressor is mounted sideways now. Don’t see how that would effect it but just ordered a Viair mounting bracket to put it right side up, its all I can think of to do at this point.
Well its definitely some thing to do with the compressor holding pressure. Yesterday morning I loosened the leader at the check valve so it would just barely leak. That way when the compressor shuts down at 200psi it will bleed off any pressure left in the leader hose. Today 24hrs later I still have all 200psi so it seems to be working.
To the OP - how old is this compressor? Does the compressor take longer than it did when it was new, to reach 200 PSI?
I’m not 100% certain, but I think that your leak is between your leader hose and the check valve. You said you replaced the check valve - but did you consider that the hose may be affecting things?
Compressor is pretty new < a year, fill rate is the same as new.
Basically what I’ve narrowed down is this:
When everything is 100% sealed and leak free (including leader), when the compressor is done filling the tank it holds enough pressure in the leader hose to keep the check valve open slightly.
My only work around was to create a small leak in the leader to bleed off that leader pressure at shut down and close the CV, doing that works. I know its weird but that’s the way it is. I’m gonna roll like that for a few days and see what happens but so far it holds 200psi. I have a Viair bracket coming in a few days that will put the comp right side up to see if maybe that’s the case.
Pic1 = Compressor mounted sideways to frame (black strap is just a safety)
Pic2 = Leader to Check valve to Tank and relay setup.
Pic3 = Output side of tank, shut off valve drain and 165/200 pressure switch
Pic4 = Gauge and 220 pop off
Pic5= McCarr Regulator, Quick Connect, and SMC Horn Solenoid Setup under the hood.
PIC2 Leader to CV is just hand tight to create the bleed off leak
When everything is 100% sealed and leak free (including leader), when the compressor is done filling the tank it holds enough pressure in the leader hose to keep the check valve open slightly.
If the check valve does not close completely, then it is not working properly. How tightly did you crank down on the check valve when you installed it?
The check valve is NPT and as such, is tapered. If you crank it down too tightly, you can cause the inner washer to become captured. This might be able to be resolved by removing, re-sealing and reinstalling - unless the check valve has been cranked down and has been permanently disabled due to over torque.
Typically, all you need is 15-20 ft. lbs and to use some good old Loctite 545 (anaerobic sealant).
FYI - it is my opinion that push-to-connect fittings are the worst type of fittings you can use. I’ve tried them and never found any that were worth a damn. Your best bet is to use brass compression fittings.
just noticed something in a reliability point of view, is the relay upside down? if it is, you should turn it around with pins facing down as it would collect water through the pins and fill up the relay with water and no way to drain. Relay gets damaged after that. happened to me once before.
Its a weatherproof relay, the connection side has a full epoxy seal on it. Pic is when I just installed it, all connections will be coted in Liquid Electrical Tape also
All VIAIR compressors equipped with check valves and leader hoses have the check valve installed at the end of the leader hose. Older VIAIR compressors’ check valves were installed at the head of the compressor. We made the move to the end of the leader hose to prolong check valve life expectancy due to the high temperature of the head assembly and the heat that was passed on to the check valve.