Testing digital manifold

bignozzle

Good morning, I just bought a used testo 557. How can I pressure test it? I don’t think it would be good to submerge in water like my old dial gauges.

Thanks in advance.

Ironman

Do you have an electronic leak detector?

ChrisJ

I'd think a reasonably quick test would be to pull a vacuum on it and valve it off and wait to see if it climbs.

I know that doesn't guarantee it won't leak under positive pressure but it's probably a safe bet.

bignozzle

no,don’t have electronic leak detector.

mattmia2

https://forum.heatinghelp.com/discussion/comment/1806120#Comment_1806120

Or better yet pressurize it with nitrogen and see if it holds.

bignozzle

I installed a vcrt on the high pressure side and put caps on the other ports. I pressurized to 300 psi. I shut valve on vcrt. I took the knobs off and put bubble leak detector around the valve stems and caps. No bubbles. I did 10 minute test and it lost .4 psi. Not sure where the pressure went.

ratio

Internal, either the transducer connection or the transducer itself.

Or, just temperature equalization. 10 minutes isn't very long.

mattmia2

Wait another 10 minutes, temp changes could account for .4 psi at 300 psi. If it keeps going down as you wait longer there is a leak, if it stabilizes or fluctuates up and down it is just error in the equipment or expansion and contraction.

bignozzle

I don’t think it’s expansion or contraction because the nitrogen bottle and the gauge were in my garage for a couple of days before.

Thanks for the input.

ChrisJ

https://forum.heatinghelp.com/discussion/comment/1806482#Comment_1806482

Hoses expanding?

mattmia2

.1% isn't a lot of electronics to drift either. give it an hour or 2, if it keeps going down there is a leak. the temp of the nitrogen changes when you change the pressure on it too although it should get cooler when you lower the pressure from the tank pressure.