CPS vg200. A bit odd

[phs]

Hi Guys Iv been using a vg200 Digi vac it's playing up some what . It seems to work ok till it gets to 110 microns then it rotates from 110 to 100 to 98 to 93 to 87 to 74 than back to 100 or 110 it keeps doing it over and over with in a 10 second period , as well I noticed when I isotate the system the gauge goes to 600 over a 20 second period , then I isolated the gauge set only so the system was nt connected and it did it again. I am using it on system that had a gas leak the leak is fixed the gas was recovered and I started the evacuation

[install monkey]

mines the same-has it got a crack from the brass body in the yellow plastic?im going to pull mine to bits at weekend

[phs]

No crack on myn but the rubber gasket is fairly worn but still grabs on tight , I'll clean the sensor then see if I can get a replacment rubber . I connected it st8 to the Pump and got it to 10 microns but it got there fairly quick it seems to play up after been on for a while

[nike123]

What hoses you connecting to gauge? You should use metal hoses or special hoses , and isolation ball valve should be rated for 20 microns.
Normal hoses are permeable and should not be used for evacuation and vacuum holding test.
Check this:
http://www.appioninc.com/downloads/files/MegaFlow_SpeedKit_Brochure.pdf

[phs]

Looks to be sorted I changed the rubbers and used metho to clean the sensor seems to have worked I turn the valves off at 300 and it holds 300 microns fine + it seems to be much steadier over the board , there CPS hoses and valves 410a rated Dunno the negative ratings there pro set CPS