Help on using IP Gauge to test reg

[fmerkel]

I got pounced on in another thread for repeating some nugget I had been told in my reg service class to the effect that piston regs tend to get out of tune more quickly than diaphragm regs. One reply called it "nonsense."

We are subject to our experience the way I see it. But some folks have a little experience and think that gives them lots of credibility. There are folks on this forum that are legions ahead of me in all kinds of areas. Sorting out the true experts from the 'know it alls' is part of the challenge. The longer I work on regs the more I tend to get 'practical' vs. 'technical'.

For getting 'out of tune' I don't have an opinion of piston vs. diaphragm. If you search SB you will sure find a lot of threads on MK 20 creep though. Once that is taken care of the reg seems to do OK, though this particular reg seems to be hell on the piston O-ring also. I'm going to polyurethane next change to see if that helps.

 

[tbone1004]

quick video on IP gauges 101. My apologies for the quality

 

[Landau]

Thanks for the video Tbone. Most informative.

 

[tbone1004]

i live to serve.

if there was anything missed in there, let me know. I'll do what I can to actually shoot it with a gopro on my work bench at some point

 

[mi000ke]

Great video - thanks for posting!

 

[herman]

A couple of thoughts on IP.
Most regs will tend to drop more than tbones on a purge or breath, its important to know what "normal" is for your reg. 10 to 15 psi is common and remember, anything in the valve or first stage can cause the IP to shift more than normal so just because it's dropping excessively it MAY not be the reg causing the problem. Swap tanks before going on a wild goose chase.
The drift tbone showed is slow and easily manageable. A creep can be a lot faster and go to full tank pressure quickly if the first stage is in bad shape. NEVER connect an IP gauge to a first stage without some kind of relief valve attached, a second stage is fine. Otherwise you risk over pressurizing a hose.....they will explode loudly....been there done that, didn't hear well for a couple of days. Its a good idea to slowly open the tank valve and bring pressure up very slowly on an unknown reg, that way if IP goes a lot higher than expected you can stop the increase before it gets way above normal.
On initial pressurization, it is not uncommon for the first stage to overshoot the IP a few psi so purge the reg a couple of times before adjusting anything.

 

[tbone1004]

@herman I was actually pretty surprised at that little piston and how little it dropped. Unsure if that is due more to the second stage being a non-high performance second stage or it just doesn't drop that much. I know my Jetstreams cause them to drop quite a bit more than most regs though. That's not a value I typically pay much attention to though. Maybe I should

 

[Dizzi Lizzi]

Thanks so much @tbone1004

 

[herman]

If it's a balanced piston then it's most likely a flow through piston which tend to have the highest flow rates of any regs. If so, the it does not surprise me it does not drop much.
Knowing what is "normal" for your reg is a good idea. A lot of things can cause the IP to drop more than expected including a clogged dip tube in the valve or a filter that has gotten clogged for some reason. The IP might be rock solid, ie HP seat in perfect condition but at the same time the reg preforms poorly due to a clogged filter which would show up as an excessive ( not normal for your reg) dip in IP during purges or more importantly during a normal breath.

 

[guruboy]

If the reg in the video with a slow lockup had drift, what is creep then?