RO system pressure gauge problem

Can anyone help?

my RO static system in my garage is playing up, the pressure gauge is not going back down to zero when I shut the water off, it goes down to about 40 psi.

any ideas why?

It could be something to do with the mechanism inside. Suggest you just buy another.

http://www.marshallinstruments.com/faqs/detail.cfm?id=22

Its been nearly 45 years since I last sold pressure gauges and I see the internals haven't changed in all those years. At one time we used to be able to get inside by removing the glass bezel, the glass, pull off the indicator arrow, unscrew and remove the dial face. The problem invariably was that curved tube although a bit of lubrication to the gears/mechanism was sometimes a solution.

Mine broke last year due to frost. Found it difficult to get to the insides, but will try to year the face plate off.

Nudel said:

Mine broke last year due to frost. Found it difficult to get to the insides, but will try to year the face plate off.

Click to expand...

 These days more and more product is made and assembled as 'sealed' and not intended to be taken apart. It all about how quickly and easily an item can be manufactured. In the old days these things were assembled by hand. Now it will be different. (Even back in 1988 a 9" Bosch angle grinder was manufactured and assembled by robots on their German production line in Leinfelden. The only manual labour was fitting the carbon brushes and they were working on a mechanical system to do that as well. When I again visited the factory in 1990 that was sorted.The manufacturing and assembly lines were staffed by just a few workers whose job it was to maintain the flow should a glitch occur. The workers car park was just about empty in 1990 where it was full in 1988. All those workers had been retrenched.)

The curved tube inside the guage will try to straighten out under pressure. The more the pressure the more the tube will try to straighten out and the greater the movement in the mechanism. Water inside the curved tube would have frozen and expanded. This would have damaged the tube's ability to work efficiently.

A gauge with the needle stuck on a reading with no pressure is a tell tail sign of this.

The inside mechanism is also suscepticible to damage due to vibration when used on machinery. This is why they fill them with glycerine as this dampens the vibration inside the mechanism.