Anyone tried running a 2nd stage from original MK15/MK15.5 1st stage reg?

koputai · 21st April 2006, 08:20

Oooh, in a KISS micra? Might have a look, thanks for the hint Dave.

Cheers,
Jason.

teksimple · 21st April 2006, 08:51

The last two weeks I have been diving with my Oceanic Air XS alternate/inflator plugged directly into my diluent 1st stage on my Mk 15.5. It works great for OC bailout at least as deep as I have tested it at 30m. There were two issues I predicted would be a problem, and it turned out that only one required any tinkering.

One was I was thinking that the intermediate pressure would be too high and cause the 2nd stage to freeflow. I did not have an intermediate pressure guage at my disposal then, but it did freeflow a very slight amount. So I adjusted the spring tension on the 2nd stage poppet valve to a bit tighter, and flipped the rubber seat for good measure. Problem solved.

The other thing I thought would be a problem is that the spare port on the 1st stage is NPT (tapered pipe, usually sealed with teflon tape) threaded, while a standard intermediate hose is UNF threaded and sealed with an O-ring. I was thinking that the 1st stage threads would cut the O-ring or tweak the threads on my hose. But I tried it with a new O-ring and no problem. Pressure tested with soap. Works great. I did have to cable clamp the hose (actually two hoses connected) up the side of my case to keep it out of the way.

So for no-deco dives, this is great. I will find out the actual intermediate pressure tomorrow if anyone is interested.

teksimple · 21st April 2006, 08:58

Quote: (Originally Posted by SteveL)

Dr M - Slightly off topic but when you are plugging and un plugging u/w are you worried about water getting into the System. I too have QC 6 swagelok fittings on the 15.5 and notice that they would hold alot of water if they were unplugged u/w. ...

Steve - I have that same fitting for offboard diluent. I got so much water in my diluent side when I started diving trimix that it flooded and destroyed my pressure gauge. In hindsight, I probably shouldn't have depressurized the 1st stages of either of my diluent supplies when underwater, but I was being extra cautious. Not sure what the solution to keep water from getting in the system is when unplugging.

***sadave*** · 21st April 2006, 10:07

Quote: (Originally Posted by koputai)

Oooh, in a KISS micra? Might have a look, thanks for the hint Dave.

Cheers,
Jason.

Sorry, can't help ya there, I've never seen the insides of one of those regs, but its a Paragon if you wanna start digging for info on it...

Good luck with it mate!

koputai · 21st April 2006, 13:47

Kent,
Depending on the history of your rig, your dil pressure could be either 8 or 18 bar. Standard is 8 bar, but some of us (including SteveL as per original post) are running a Mk16 dil 1st stage spring to give us plenty of drive on the ADV.
If you're getting a 2nd to run ok, I suspect you're running 8 bar.

Cheers,
Jason.

21st April 2006, 08:20	#11 (permalink)
koputai Subsea Systems Current Rebreather/s: MK 15.X Other CCR Other SCR Other Rebreather/s: Not Bought Yet Other CCR Other SCR Join Date: Jul 2005 Location: Sydney, Australia Posts: 340	Re: Anyone tried running a 2nd stage from original MK15/MK15.5 1st stage reg? Oooh, in a KISS micra? Might have a look, thanks for the hint Dave. Cheers, Jason.
(Offline)

21st April 2006, 08:51	#12 (permalink)
teksimple Enlightened Alpinist Current Rebreather/s: MK 15.X Other Rebreather/s: Sport Kiss Classic Kiss Join Date: Apr 2005 Location: Back in Hawaii Posts: 503	Re: Anyone tried running a 2nd stage from original MK15/MK15.5 1st stage reg? The last two weeks I have been diving with my Oceanic Air XS alternate/inflator plugged directly into my diluent 1st stage on my Mk 15.5. It works great for OC bailout at least as deep as I have tested it at 30m. There were two issues I predicted would be a problem, and it turned out that only one required any tinkering. One was I was thinking that the intermediate pressure would be too high and cause the 2nd stage to freeflow. I did not have an intermediate pressure guage at my disposal then, but it did freeflow a very slight amount. So I adjusted the spring tension on the 2nd stage poppet valve to a bit tighter, and flipped the rubber seat for good measure. Problem solved. The other thing I thought would be a problem is that the spare port on the 1st stage is NPT (tapered pipe, usually sealed with teflon tape) threaded, while a standard intermediate hose is UNF threaded and sealed with an O-ring. I was thinking that the 1st stage threads would cut the O-ring or tweak the threads on my hose. But I tried it with a new O-ring and no problem. Pressure tested with soap. Works great. I did have to cable clamp the hose (actually two hoses connected) up the side of my case to keep it out of the way. So for no-deco dives, this is great. I will find out the actual intermediate pressure tomorrow if anyone is interested.
(Offline)

21st April 2006, 08:58	#13 (permalink)
teksimple Enlightened Alpinist Current Rebreather/s: MK 15.X Other Rebreather/s: Sport Kiss Classic Kiss Join Date: Apr 2005 Location: Back in Hawaii Posts: 503	Re: Anyone tried running a 2nd stage from original MK15/MK15.5 1st stage reg? Quote: (Originally Posted by SteveL) Dr M - Slightly off topic but when you are plugging and un plugging u/w are you worried about water getting into the System. I too have QC 6 swagelok fittings on the 15.5 and notice that they would hold alot of water if they were unplugged u/w. ... Steve - I have that same fitting for offboard diluent. I got so much water in my diluent side when I started diving trimix that it flooded and destroyed my pressure gauge. In hindsight, I probably shouldn't have depressurized the 1st stages of either of my diluent supplies when underwater, but I was being extra cautious. Not sure what the solution to keep water from getting in the system is when unplugging.
(Offline)

21st April 2006, 10:07	#14 (permalink)
*sadave* Waiting... Current Rebreather/s: Sport Kiss Other Rebreather/s: Not Bought Yet Classic Kiss Join Date: Jun 2005 Location: Brisbane, Queensland Posts: 1,041	Re: Anyone tried running a 2nd stage from original MK15/MK15.5 1st stage reg? Quote: (Originally Posted by koputai) Oooh, in a KISS micra? Might have a look, thanks for the hint Dave. Cheers, Jason. Sorry, can't help ya there, I've never seen the insides of one of those regs, but its a Paragon if you wanna start digging for info on it... Good luck with it mate! __________________ Wave!
(Offline)

21st April 2006, 13:47	#15 (permalink)
koputai Subsea Systems Current Rebreather/s: MK 15.X Other CCR Other SCR Other Rebreather/s: Not Bought Yet Other CCR Other SCR Join Date: Jul 2005 Location: Sydney, Australia Posts: 340	Re: Anyone tried running a 2nd stage from original MK15/MK15.5 1st stage reg? Kent, Depending on the history of your rig, your dil pressure could be either 8 or 18 bar. Standard is 8 bar, but some of us (including SteveL as per original post) are running a Mk16 dil 1st stage spring to give us plenty of drive on the ADV. If you're getting a 2nd to run ok, I suspect you're running 8 bar. Cheers, Jason.
(Offline)

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