invisable air leak

i have a slow leak in my system that will not show up with air bubbles. about 10psi every 5 hours. nothings showing up and its not the airline to the horns? any help would be great.

So you tried the soap / water on every fitting? and even on the seams in tank?

Is it mainly overnight u notice it most? If the temp drops at night by you like it does in ny . the cold finds any small pin hole leak…

The reason you would loose pressure overnight because air expands with heat, opposite when you cool it.

I loose about 5-10 overnight, and get it back by mid morning, not a leak.

I had a leak in a cheap needle gauge I had on the side of the tank, if you can’t find it at the fittings, start blaming the fixtures, valves, pump check valves.

it does it during the day. i have checked everything else. any other tips?

Could the air be leaking back through the compressor? Are you using a check valve?

Yes I think so. I bought the kit from hornblasters. A vair 480 compressor. It does come with one if im not mistaken.I believe it is on the end of the outlet hose. I also put a baloon on my hose goin to my horns to leak check it and nothing showed up.

You need to double check that the check valve is not leaking.
I bought on of these at an industrial shop. It works flawlessly.

how can I check the check valve?

^ Fill the tank, then remove the hose opposite of the tank. Then you can take soapy water to see if the inside of the check valve is leaking or not.

hey guys. new to this. im also having a leak problem. i checked all the fittings and im using a pretty cheap 200 psi sears gauge. i didnt look at my check valve but i have a 480c viair that is like 4 days old. any ideas?

Ya, look at you check valve.