manifold gauge

[robin r33 gtr]

Do people use their manifold gauges for strength testing or do you have a separate high pressure gauge just for this job?

If so what gauge do you use ?
Is it OK to use any high pressure gauge ?

[sedgy]

have you a nitrogen bottle regulator?
it would be better to use this

[robin r33 gtr]

I do have a nitrogen regulator ,but if I had a 10 psig drop over 1 hour or so the gauge would not be accurate enough to show the drop.

For example. when I have a leak on a vrv I pressure test and shut the service valves and attach 1 gauge to the condensor and 1 gauge to the pipe work and leave it over night. To do this I use 2 sets of gauges.

[chemi-cool]

Use 410 high side gauge.

Look for the biggest you can find, its the most accurate.

[VRVIII]

Do people use their manifold gauges for strength testing or do you have a separate high pressure gauge just for this job?

If so what gauge do you use ?
Is it OK to use any high pressure gauge ?

A proper pressure testing rig should be used for strength testing 410a (40bar) these are readily available from most suppliers.
I use a Javac rig
http://www.javac.co.uk/nitrogen-pressure-regulator-uk-c-302-p-1-pr-16242.html

[Peter_1]

You can use a 1-way manifold like this or use just thus the dial without a valve on it. I never leave a manifold on the system while testing for leaks.

A good technique nowhere explained in books: you pressurize the system with a full nitrogen bottle till everything stabilizes on the desired pressure.
You have your pressure regulator which will show you let's say 25 bar on you system side (LP side) and 150 bar on the OFN side (HP side).
The LP side is a small pressure but big volume compared to the HP side with its high pressure and very small volume( only the pressure diaphragm in the regulator)

You close only the valve on the OFN bottle and let the pressure on the regulator.

We have the Gas law (Boyle) which states P x V = ct
So the smallest leak on the LP side will drop the pressure very fast on the HP side because the regulator will try to maintain pressure but there's no volume to do this, so HP will drop and drop very fast. Try once.

[robin r33 gtr]

Thanks for all the help.

[monkey spanners]

I have a single gauge one like Peter showed made by refco.