Pressure gauge question

[D Smyth]

I have installed a pressure gauge in my water system but it doesn't seem to work. It's plumbed into the copper tubing so I know there is pressure on it. The gauge, which I picked up in a bargain bin, has two scales, each covering

50-350 psi... One is labelled LEG CURL and the other LEG EXT. The gauge also has what looks like two set screws, one on either side of the dial housing and two more screws on the back. a)Is the gauge defective b)Is it the wrong kind of gauge or c)Does it have to be adjusted somehow. Thanks ds

[ConRes]

For something like residential water you will probably need a 6" gauge with less than 100 psi. If your gauge is any smaller than 6" you won't be able to read it as the gradients will be too small. Rich