SP Mk25/S600 vs Apeks ATX200 questions

[LG Diver]

I've been using an Apeks ATX200 with ATX50 backup for single tank diving. I just bought a pair of SP Mk25/S600's for my new doubles rig and had some observations and questions:

1) The S600 regs (both of them) will freeflow uncontrollably on the surface if I depress the purge button with the inhalation control knob all the way open. I have to screw it down about 3/4 of the way to stop the freeflow, and to be able to press the purge button without it freeflowing. The dive/pre-dive knob doesn't make a difference. Is this normal? On my Apeks regs I had the knob all the way open and in "dive" mode all the time and never had a freeflow issue. Also, pressing the purge button on the S600 delivers a TON more air than the Apeks.

2) At depth (40' - 50') I opened up the inhalation control to about 3/4 way open, and was amazed at how much easier the S600 breathed compared to my ATX200.

I've heard other people say that there's no real difference in WOB between these two regs, so these two observations together make me wonder if there's something wrong with my Apeks regs. Any thoughts?

 

[mtbrider]

Well, it's hard to compare without having both regs set to the same cracking pressure, etc.

However, I have a set of the MK25AF/S600 and I bought my girlfriend the DS4/ATX50. I tuned all the regs up myself, and I must say with the S600 you can really set the cracking pressure low for easy breathing. With the ATX50 it is not as sensitive; also the ATX50 venturi assist is actually too extreme in the full + position.

You mean you can't stop the freeflow on the S600 regs if you get it started? Even with the mouthpiece down? That seems weird. I think the dive/predive knob is just to 'help' with freeflow, not keep it from happening altogether.

I set the cracking pressure on my S600 so that with the knob fully open it just barely bubbles in a face down position. I can then adjust the knob from there depending on what I'm doing.

Sounds like your ATX200 needs to be tuned up.

 

[LG Diver]

What I mean by freeflow is if I depress the purge button it feels like it sucks the diaphragm in and holds it there and will not stop flowing. This happened out of the water when I was setting up the regs on the tanks. Not the typical freeflow when a reg contacts the water face-down. BOth regs do this unless the knob is about 3/4 closed.

 

[Blitz]

The one thing that I have noticed is that the S600s breathe drier.

 

[mtbrider]

Hmm, I'm not sure if my regs will freeflow like that outside of the water. I'm guessing you can get it to stop by sticking it in your mouth of putting your hand over the mouthpiece?

I will check it out tonight and let you know what I find.

 

[Divedoggie]

The regs should be adjusted. If adjusted properly, they should breath about the same, and crack about the same. If out of adjustment, who knows if it will free flow, or if the WOB will be super difficult.
Have a certified tech adjust them.