DiveRite Sidemount Regulators - XT vs RG3ICE vs 212/DC1

[eelnoraa]

How often, in your experience, do 2nd stages ice up before the 1st stage? I asked my Tech instructor how to tell if my recent free flows were 1st stage or 2nd stage problems and he said it would be hard to tell but in his experience free flows are usually a result of the 1st stage icing up. The more I think about my recent ones, the more I'm inclined to think they were from the 1st stage icing up, not the 2nd stage.

In other words, does the air barrel material in the 2nd stage REALLY matter (regarding cold water use)?

Now you are not talking about the same topics. We were on if plastic barrel is better than metal for cold water. The answer to that is definitely NOT. Metal barrel is superior than plastic barrel for cold water. I don't even think there should be an argument here.

You just brought up how often I have 2nd stage ice up. The answer is NEVER. The coldest I have dived is 42F. While I am pretty sure plastics barrel will not freeze up under normal circumstances, it doesn't mean metal isn't better. A noticeably difference will be moisture in breathing gas. In fact, I can even notice it between M1 (brass barrel) vs B2 (titanium barrel). Plastic will definitely be infereior in this case as well.

I think the key is if you already own plastic barrel 2nd stage and it works, it is all good. For someone who is thinking about getting new reg, I would say go for metal barrel model. And we know for a fact that you can do that for same or lower cost.

 

[ams511]

Anyway... I attribute the fact that both 2nds didn't FF simultaneously to the fact that I leave my alternate set to Pre-dive and with the inhalation effort knob turned a couple of turns away from the easiest setting, to help stop it from free flowing when I first jump in.

If your first stage is frozen open the IP is going to rise. Your primary will start first because it is more sensitive but the octo will begin shortly after regardless of the settings. The dive/predive switch only affects the venturi not the cracking pressure. The fact that you were able to breath off the alternate for a while makes me think it is not a first stage problem. I would check the IP on the regulator and set it on the low side before diving in cold water again.

---------- Post added August 14th, 2015 at 12:39 AM ----------

Ahhhh, yes. I can ALWAYS count on ScubaBoard to turn any thread into a "your instructor is incompetent" thread....

I was not trying to derail the thread but I do consider your instructor's behavior as you described it to be unacceptable.

 

[stuartv]

Can you confirm. You were diving single tank, only one fist stage?

"Pre-dive and with the inhalation effort knob turned a couple of turns away from the easiest setting" will not have any impact on a 1st stage free flow, 500-3000psi in the IP hose! Unless you tank pressure was about 140psi, and then with the free flow you would have an empty tank almost instantly.

Your second stages are the issue, assuming you are diving both on the 1 first stage.

Yes, single tank.

Gotcha. I figured I increased the cracking pressure on the alternate 2nd stage, so that made it where the other one started to FF and that relieved the line pressure enough to not make the alternate start. But, I hear what you're saying about the line pressure being so high that they would both FF. My tank was nearly full (and a HP120).

Now you are not talking about the same topics. We were on if plastic barrel is better than metal for cold water. The answer to that is definitely NOT. Metal barrel is superior than plastic barrel for cold water. I don't even think there should be an argument here.

It seemed like the same topic to me because my point was that if it's not (or almost never) the 2nd stage free flowing, then it seems it doesn't matter (with respect to icing in cold water) whether the air barrel is metal or plastic. But, tbar I think has cleared that part up and so I can go with yes, it was my 2nd stage in FF, not the 1st stage. Thus, yes, the air barrel material does matter.

If your first stage is frozen open the IP is going to rise. Your primary will start first because it is more sensitive but the octo will begin shortly after regardless of the settings. The dive/predive switch only affects the venturi not the cracking pressure. The fact that you were able to breath off the alternate for a while makes me think it is not a first stage problem. I would check the IP on the regulator and set it on the low side before diving in cold water again.

Got it. Thanks!

 

[stuartv]

I ordered and have received a set of the Dive Rite XTs. Have I mentioned that Dive Gear Express is awesome?

Last night, I hooked up the XTs and my Hollis regs, switching back and forth on the same tank. I tried all 4 2nd stages (both Hollis 2nds on the same Hollis 1st, and each XT2 on its own XT1). This was all done in my house, not in the water.

My observations:

- The Hollis inhalation effort knob has a range of adjustment that must be about 10 turns. The XT2 adjustment goes from all the way one way to all the way the other in less than 1 turn. Both make a noticeable difference in inhalation effort, but you have to spend some time turning the Hollis knob before you notice much change.

- With the Dive/Pre-dive switch set to Dive, the Hollis 2nds free flow at the tap of the purge button. But, they stop instantly when I would flip the switch to Pre-dive. The XT2 was definitely more reluctant to free flow just from tapping the purge.

- With them all set to Dive and the inhalation effort turned to "easiest", the Hollis regs seemed just slightly easier to draw from. I'm not talking about the cracking pressure. I didn't really notice a difference on that. I'm talking about once the 2nd cracked and I was drawing air in, it seemed like the "resistance" to drawing air into my lungs was just a tiny bit higher with the DR regs than with the Hollis. Not sure what that means and I suppose it could have just been my imagination. But, I felt like I could detect the same differences with both DR regs and both Hollis 2nds.

Next step will be to temporarily modify my Hollis set to use with doubles. I'll probably just take my alternate and BC inflator off, leave the AI xmitter on, and put it on the right post. Then go do a test dive in the quarry and compare the Hollis set on one post to the DR set on the other post and see if I can tell any difference in real live usage. Not that I'm thinking of returning the DRs or anything. Really just cause I am curious about these things.