How much IP Creep is acceptable ?

[ozziworld]

I have observed some creep on my MK5.

Reading an IP gauge attached to the inflator hose, at 2500PSI Tank Pressure.

Initial Reading 140PSI

Take a normal breath from 2nd Stage - PSI drop then bounces back to 135 PSI and takes a second to go up to 140 PSI.

This is basically the repeatable pattern.

However, when I leave it pressurized. Reads 150 PSI after about 2 hours. Have not tried leaving it pressurized for more than that.

Seems this would indicate a need for service. I have been using this regularly but have only maybe 50 dives on it over last year. Seems kinda premature.

 

[tbone1004]

officially that's probably a bit much and I would recommend service. Would I still dive it? yes.

 

[Diver0001]

Creep is when it keeps going up beyond the 145 you set it to. The first thing you were describing doesn't fall into that category, the second does.

I've heard people complain about creep issues on certain SP models before. One of my buddies finally sold all his SP regs and bought Aqualungs because he couldn't get it to stop and it was driving him nuts. I think he serviced his regs about 3 times a year when he was diving a lot.

In principle the idea that your reg is creeping and you know it's creeping isn't going to make you trust it more. So if you see it creeping, the best thing you can do is get it serviced.

On a practical level, when do you ever take 2 hours between breaths during a dive? if your 2nd stages are unbalanced then try leaving it on for 24 hours and see if it starts to free flow at some point.

R..

 

[ozziworld]

Thanks for the input Diver0001.

One of those things that it is the same reg that I have been diving. Only difference in now I am ware of some creep. Yeah, in practice it would never be noticable. Just wondering if that would become progressively worse.

It is a 25 year old reg and way past it parts for life I probably service it every two or three years. This one just came up sooner than expected.

 

[tbone1004]

I personally wouldn't worry about it as long as you are OK diving it, it doesn't sound that bad and some scubapro's are prone to this behavior

 

[redacted]

I set IP on the low side (125 to 130) and moniter it often. When a 2nd stage starts to hiss (are you sure yours was not?) it is a must service. With the amount of creep you report, I would probably div e it but I would not pack it for a dive trip.

I really suspect yours is hissing ever so slightly and should serviced. I have never seen one get better on its own.

 

[halocline]

It is a 25 year old reg and way past it parts for life I probably service it every two or three years. This one just came up sooner than expected.

If it's a MK10 or MK10+ the slightly mushy lock up (135-140 in a few seconds) is pretty typical. The slow creep after that is a problem, probably caused by a very tiny leak at the piston edge. If you took it apart and inspected the piston edge with a jeweler's loupe, you'd probably see some small flaw. It is possible to polish those flaws out and get rid of the creep. But you'll never get a SP dealer to do that, they'll want to replace the piston. If by some chance it's a MK20, you can get the MK25 composite piston for it, and that should solve the problem.

I would leave it pressurized overnight and see what happens. Sometimes they'll creep up to a high IP (like around 150 or so) and then stop because the high IP adds enough pressure on the piston to seal the very small leak. But more often they'll just keep slowly creeping until a 2nd stage starts to flow.

If it's a diaphragm reg, sometimes the tiny o-ring in the balance chamber starts to leak, letting HP air into the IP chamber. This usually is a result of a scratch on the balance chamber from a sloppy tech removing the o-ring.

Edit: I finally looked closely enough at the first post to see he has a MK5.....sorry about that, but this information is still valid, except IME MK5s lockup very solidly.

 

[ozziworld]

I did just that. Left the MK5 pressurized overnight and it stayed at 150 psi. I have another MK5 and it does the saem thing with intitial lockup and a quick creep to 140. This one stays at 140 though.

 

[halocline]

My MK5s lock up perfectly and are very stable with IP. What kind of seats are you using? And what durometer/material are you using for the HP piston stem o-ring?

 

[ozziworld]

Halo, afraid I don't know the answers to you questions but the rebuild kits were from vdh if I recall correctly.