1st Stage question / MK25 EVO swapping

[jmhetmanski]

I have a two newly acquired (and new) first stages: MK25 EVO one yoke and one DIN. I also have 2 new G260s. My question: I'd like to switch the second stages back and forth between the first stages depending on tank rental availability when traveling. (I'm not a fan of DIN to yoke adaptors). Anything I need to consider or do to make this work w/o issue? Thanks in advance for your thoughts.

 

[NDonahue]

No issues at all. Swap away.

You could buy an adapter for $50 and sell the Yoke version. You’ll spend $70-$100 every time you get that extra first stage serviced.

 

[Nemrod]

Swapping a Mk25 back and forth from DIN to A clamp is not a big deal and easily done by anyone with a modicum of skill with rocks, fire and the occasional tools. The Scubapro Mk 25 uses the Scubapro Universal DIN kit here:


Or carry DIN inserts for "Pro" type valves.

 

[207diver]

The G260 is balanced so any variation in IP between those two first stages shouldn’t be noticeable or a problem. Nothing to worry about. Go for it!

 

[Nemrod]

The G260 is balanced so any variation in IP between those two first stages shouldn’t be noticeable or a problem. Nothing to worry about. Go for it!

Exactly and the Mark 25 has externally adjustable IP so it would be failry easy to match them up close enough. But a G250 or G260 or any balanced regulator is not going to care much either way with an IP as long as it is within tolerance specs.

DIN tanks can be rare in some areas, the Caribbean in particular and even those with convertible valves (Pro type) the inserts might be so corroded or peened in place from the valves having been dropped that removal could be a challenge. A clamp converters work in a pinch but are not ideal.

 

[BoltSnap]

Put both G260 seconds on each first stage on a full tank and make sure that all is OK with the adjustment knob all the way OUT. Take several "heavy" breaths from each second stage on each first stage. You should be OK.

 

[Pressurehead]

even those with convertible valves (Pro type) the inserts might be so corroded or peened in place from the valves having been dropped that removal could be a challenge

This was the case on my last resort dives over a week, inserts "so corroded or peened in place" it was a PITA when I took my DIN Mk19 [and G260 and S600].
Off topic I know, anyway.
I change 2 G260s between Mk25 DIN, Mk19 DIN and Mk17 Yoke, DIN or Yoke no problem at all, easy , the IP is close enough + or - , 4/5ths of 5/8ths of bugger all .
I do carry a DIN to Yoke adapter just in case [I just don't like to use it].

 

[Nemrod]

As pointed out if a second stage were adjusted hot with a first at 125 psi IP and then installed on a first stage with an IP of 145 then there might be a second stage leakage with the tuning knob all the way out. Either turn it in or perhaps better, adjust the first stage pressure down. The accepted IP for a Mk 20/25 is 125 to 145 psi and for the most part, a G260 will not care unless, again, it has been tuned hot as some of us prefer.

Pry (gently please and might use hot water run over it) the plastic bump cover off of the Mk 25 and adjust the IP down to match the lower set IP of the other first stage:



Note the warning, adjust the IP with the first stage purged of any pressure. It may take several small adjustments and cycling the first stage for it to settle in to the new setting.

 

[jmhetmanski]

Thank you all - very helpful indeed!

 

[buddhasummer]

Worthy of another warning especially if you're coming from diaphragm first stages.

"Note the warning, adjust the IP with the first stage purged of any pressure...."