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scubapro mk25 first stage - ice-free?

  • had problems / would be careful if i were you

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<font color='#000080'>probably a bit late as i've already bought this reg, in fact i've had it for a while but have been using it on my pony and not used it much.

it's a scubapro mk25 R80, and now that i'm twinning up (indy 7s) i'll be using it a lot more. the mk25, although a piston first stage, claims to be resistant to icing-up due to various features.

does anyone have any experience of this reg, if so do you reckon it's any more likely to freeze than my apeks first stage?

cheers, kate
 

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To dive or not to dive - that's not even an option
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Watch out!

Scubapro make a couple and the one for very cold conditions has different letters "AF" I think. You may want to try their web site for clarification. The Apeks are probably the safer bet as all of their range with the exception of one pony reg is designed for cold water.

James
 

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I run two Mk25s, one "normal" for the past 3 years and a new "AF" with vanes and enlarged holes for a few months. I've done many 3-4 degree dives and never had a problem. Mind you I have never tried "abusing" the Mk25 i.e getting it wet predive and breathing off it like an animal at the surface

 

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A man of many talents - sadly all well hidden...
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I experienced a free flow with an MK25/S600 on Saturday after deploying a DSMB using it in 8 degrees.

Fortunately we were very shallow and my buddy shut off the valve, opening it again cleared the problem. I confess that I've been using the reg for a year, including some pool work, without having had it serviced but I am a bit concerned given that 8 degrees is not the coldest I'd expect it to perform perfectly in and I don't mistreat it.

I haven't used the reg colder than that and up until Saturday it had been extremely well behaved.
 

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Never had any problems with MK25's with S600 or G250 second and I use them all year round in inland sites (so 4 degrees min).

Tony F - how was your second stage set (knob wound out/in, VIVO open/closed)? Also, whats the Intermediate Pressure of your 1st stage???
 

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I've had one free flow in a year and a half of using my Mk25 with S600. It happened at around 26m in 4-5°C in Vobster. However I had used it in similar tempratures a couple of times and it's been ok.
 

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Use two MK25s one with a S600 the other with S550, had no problems in the last two years, diving all year round.
 

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DJL said:
Never had any problems with MK25's with S600 or G250 second and I use them all year round in inland sites (so 4 degrees min).

Tony F - how was your second stage set (knob wound out/in, VIVO open/closed)? Also, whats the Intermediate Pressure of your 1st stage???
Oh dear, technical questions..... you see, this is why I never venture into these threads ;)

The VIVO was set to the Dive position, and the cracking pressure knob (venturi?) is set to about half way. I realise the VIVO is there to prevent freeflows but I think that's just about the transition from air to cold water........ but on my Octopus I leave it set to Pre Dive.

The cracking pressure knob I do move periodically so it doesn't become fixed but I normally set it to about the half way point as I find that comfortable and to be honest it felt comfortable on Saturday so I hadn't re-set it. This was the second dive by the way and I had deployed a DSMB on the first using it without issue.

I confessed earlier that as I've never had this kit serviced I have no report on the actual intermediate pressure of my 1st stage but I believe it comes standard at around 9.5-10 bar.

It's a sealed reg sold as suitable for cold water diving but having checked I now appreciate to Scubapro this means water down to 10 degrees normally. So at 8 degrees and having just dealt with the blob I suspect I was pushing my luck a bit and I possibly had a small ice partial form in the second stage. I should've maybe turned down the venturi or been more gentle with the purge when inflating the blob. Maybe that would have helped.

Given I've had it a year even though it hasn't had massive use I think a service is in order however just for peace of mind?
 

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Both the wife and I have both recently suffered free flows in cold water at stoney from our Mk 25AF S600. Both were just over a year since last service, got them serviced and now problems since, even in colder water. Used to use MK20's all the time and have never had any problems with them, the MK25 is just a tweaked version so really there should be no difference in cold water performance. I suspect that the MK25's are tuned quite highly to get the performance and as such they need more maintainance. The annual service is possibly more critical than on older regs, best analogy a sports car needs to be tuned and serviced more often to get the best performance than the family Mondeo.
 

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The Duck said:
I've had one free flow in a year and a half of using my Mk25 with S600. It happened at around 26m in 4-5°C in Vobster. However I had used it in similar tempratures a couple of times and it's been ok.
Vobster has a knack of freeflowing regs, It was by the Plane Centre section was it ? We've had 3 or 4 freeflows at exactly that point over the last year, all temps & only at that point Spooky or what.
 
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