On Feb 27, 9:51*am, Ignoramus27827 ignoramus27...@NOSPAM.
27827.invalid wrote:
I have this gauge:

http://cgi.ebay.com/ws/eBayISAPI.dll...m=250361252136

I put it on a wall to show pressure in my compressor tank (before
filter/regulator).

It works, however, it shows pressure about 25 PSI too low. It is very
easy to see, as the pointer arrow starts rising only some time after
the compressor starts pumping, and stays 25 PSI below the .

25 PSI seems to be a consistent difference regardless of pressure. In
other words, I just need to find some way to turn the arrow to point
to 25 PSI more and it will be accurate.

My obvious question is how are these gauges usually adjusted.
--


Is it possible the gauge is not calibrated in PSI? I have a similar
gauge and it reads in "feet of water"
feet of water * 0.4335 = PSI.
40 feet* 0.4335=17.3 psi 40psi?-17.3psi=22.7psi (approximately 25)

Cool gauge either way.
Good luck,
Andy