Do I have a leak?

[Pizzaman2976]

Hi All, 

I recently purchased an Omega 100 cu ft tank and had it filled at 4,500 psi a few days ago. I still haven't filled any airguns with it, but I'm noticing now on the tank valve that it's just slightly under 4,000 psi. What gives? Does it fluctuate this much right after a fill?

For what it's worth, the tank was very warm after the first fill and the gauge was actually reading slight above 4,500 (I assumed because of the heat). 

 

[2fast2furious]

That is normal. Usually at the shop they will fill it to 4500 psi. Wait for hours and refill it again to 4500 psi. I guess the shop you fill at was being lazy and did not wait for it to cool down and refill it. If there was a leak, it will just keep dropping in pressure and you will hear hissing sounds 

 

[Pizzaman2976]

Thank you! That makes sense and I'm glad to hear this seems normal. I would have assumed if there was some leak the fill shop would have noticed and let me know. 

 

[JCD]

Its been years, and the shop closed... But they filled mine to 4500 a couple times only to find out it was below 3800 by the time I went to use it. The owner was a friend of friend and he said IF I could leave it, he would fill it and then top it off the next day. For me that meant a day or two off shooting. But yeah they get hot during filling so when they cool the pressure will drop. 

I fill my own now and see about the same pressure drop but it's not a limitation for me anymore, just have to fill the tanks more often.

 

[Gerry52]

#1) a lot of dive shop's compressors only fill to 4200psi (high pressure SCUBA tank) so, at first it looks like 4500psi when tank is warm but can drop a few hundred lbs as it cools. #2)With an SCBA (carbon composite) tank it's usually a "2 step fill (fill to 4500psi on guage, let it cool, then top off to a true 4500psi) Luckily I have a shop that will "fill" my SCBA tanks then top off the next morning. NOT unusual to lose 500psi upon tank cooling down. I don't believe you have a leak, just air contracting as it cools.