O2 clean MK 25

[halocline]

Ok, as most dont realise they are a little more complex than the more simple regs, and with an expensive orifice if damaged. I would use an O2 kit if available especially if using very high levels of oxygen.

I would probably open it up and clean at least just to ensure its not going to attract damage from water.

MK25 with an orifice? Sure about that? Are you talking about the piston....

 

[halocline]

I had an oops moment and got seawater in my first stage. I wouldn't worry too much except it is my deco reg. I have a spare standard service kit. Do I really need the official oxygen compatable kit and if so anyone got one they want to sell me at a reasonable price?

Its been functioning flawlessly but its been two years since the original service so if figured I would just do a full service since I needed to open it up anyway. But an inspection and cleaning may also be an option.

Opinions?

Thanks Guys

Just so you know, I have a friend with a MK20 I serviced almost 10 years ago and it's still working perfectly. IMO there's no reason to service your MK25 simply because it's had 2 years of use, especially as a deco reg, which I assume means fewer hours of use than your back gas regs. I guess it depends in part on the gas.

If you're using this reg for really high blends of O2, like close to 100%, the typical o-ring material is viton (flourocarbon) but Parker lists EPDM as similarly compatible with "cold oxygen". It's only high temp O2 where EPDM gets a poor rating. I also found another document about ignition temps for materials used with pressured O2 and flouroelastomers (viton) are listed at 600F, polyethylene at 360F. I don't know exactly where EPDM would fit in with the polyethylene.

I guess the point is, it looks like the difference between viton and EPDM o-rings for O2 use in scuba regulators is minimal. I also suspect, but I'm not certain, that the only difference between the MK25 standard and 'nitrox' kit is the use of viton vs EPDM o-rings. So I would use either.

I think dumpster diver's idea is a good one as long as you are confident that you can get the seawater out before it dries and corrodes the HP section of your reg. You could remove the seat retainer (leave the seat in the retainer) and DIN retainer, and that would give you better access to soak the parts most likely affected. You could also then inspect and clean or replace the filter.

One more bit of unsolicited advice; as long as you are self-servicing, you might consider getting a used MK2 for use with high O2 blends. The reason is that there is much less plastic and elastomer material for potential ignition. Keeping a MK2 O2 clean is extremely simple and economical, they last forever between rebuilds, no dynamic o-rings under high pressure, it's just an ideal O2 reg.

 

[redacted]

There was a time, back in the voodoo gas age, that scubapro produced a separate kit for Mk20 EAN use, but it was still not for use with 100%. It had an HP seat that was O2 green and different color o-rings, all with different part numbers. I do not believe such a thing still exists. I suspect an O2 clean Mk25 ( or any other SP reg) uses the standard kit with the extra O2 cleaning process. You might just pull the seat retainer and see what color the seat is. My money is on black.

I would clean and lube what you have.

 

[akdeepdiver]

I've got 2 of the MK20 O2 service kits I'd part with for a decent price. Or if you think to switch to MK2s for deco I have 4 in yoke and 3 in DIN I'd part with for $75 each. Email me if interested.

 

[NotSure]

I found it interesting that the instructions for the MK20 EAN Kit AWAP mentioned not only say that no Scubapro regulator designed for air should be used for 100% oxygen, it also says that the kit itself does not come O2 clean.

 

[dumpsterDiver]

I was going to say the exact same thing, why are you using a high end, first stage with a swivel for an oxygen reg? I have one MK-2 which I must have bought 6-8 years ago and has been used continuously on a pony bottle, In reality, it is actually "used" almost never, but it has many, many dives on it. I always soak and rinse it but it has been prefect with no leaks at all.. Now I jinxed myself,,

Also, my SP swivel first stages (5, 10, 20) seem to work pretty well, but they do not have anywhere near that kind of longevity between required service.

 

[uncfnp]

Update. I was in the midst of an eight day diving vacation and needed the regulator so I took dumpsterDiver's, et al's advice and gave it a good rinse. Then at the LDS I mentioned my problem and their tech just happened to be in, overheard my conversation, had nothing pressing to do and told me to bring it in.

Back in his shop he gave me a bucket to fill with hot water and when I returned he set to work on the regulator. I asked if I could watch over his shoulder. "No problem." OMG it was almost worth the saltwater intrusion to get to see a real live tech at work. Most of what he said just confirmed what the usual suspects on SB have shared over the years but it was still a wonderful 15 minutes or so.

He started with looking through the slots and giving his approval then opening the DIN and giving this section an ultrasonic bath while also giving the filter the all clear. So he just replaced those o-rings, put it all back together demonstrating his "torque" method and had me test it out. All while giving me the third degree. I think I passed cause he gave me the days he is in the shop with a standing invitation to stop by anytime. Unfortunately I wouldn't be back for many months. Cost? A six pack of Red Bull but I brought him a case instead.

@dumpsterDiver The MK 25 was a gift for just this purpose so I am relunctant to replace. But the MK 2 sounds like a sound idea so I might just have to contact @akdeepdiver. Something to consider.

But in the meantime I still plan to open it and take a good look when I get back home and make sure all is well.

@halocline and @NotSure I use it on pure 100% Thanks for the info.

@awap I will let you know the color of the seat. It damn well better be green! Better yet, for the price I paid, golden!

Thanks guys!

 

[redacted]

@awap I will let you know the color of the seat. It damn well better be green! Better yet, for the price I paid, golden!

Thanks guys!

Don't get excited if it is black as I expect. Back in the early days, Mk20 seats were either green or white. Now they are black and I suspect they are OK with all O2 levels.

 

[bl6394]

Thanks. I take it then that the standard Scubapro service kits do not have 02 compatable o-rings. Looks like its dumpsterDivers suggestion until I can scrounge a suitable kit.

Scubapro does sell an oxygen compatible kit for the Mk25 - the one from last year and this year had a green seat. The standard Mk25 service kit is only compatible with up to 40%.

If you flooded it with salt water - I would recommend servicing it. Outside of the flood - the manufacturer recommendation would be to service it every 2 years (or 100 hours of use) - whichever came first. If your goal is to clean the regulator for oxygen service - more than a soak in distilled water / bucket of hot water is required - but it is something you could do yourself.

PS - I prefer the Mk2 as a deco reg. It's stupid simple, the kits are cheaper, and it breaths just fine at 20 ft.

 

[bl6394]

I also found another document about ignition temps for materials used with pressured O2 and flouroelastomers (viton) are listed at 600F, polyethylene at 360F. I don't know exactly where EPDM would fit in with the polyethylene...

Assuming 1500 psi (10.3 Mpa) gas - you'll find the following autoignition temperatures :

FO2 21% 50% 100%
______________________________________
Viton 610F 563F 554F
EPDM 399F 379F 369F
Polyethylene 383F 363F 348F

Source:
Flammability and Sensitivity of Materials in Oxygen-enriched ..., Issue 1395
By Theodore Aaron Steinberg