DIR- GUE Importance of having matching primary and backup regulators?

[Ayisha]

My primary second stage is a G260, but my backup (necklace) is a budget R095. Both Scubapro, in case that wasn't clear.

How important does the community feel it is to match the primary and backup regs? That would mean me buying another G260.

I did Fundies with my Sherwood Blizzard primary and Sherwood Brut backup, and my instructors didn't complain. I later switched to a Blizzard for my backup as well. They may not be cool, but they're workhorses and reliable in our freezing water.

If they breathe well, they're well maintained, reliable, and you like them, that's really all that matters.

 

[Alaskan Scuba Dude]

My primary second stage is a G260, but my backup (necklace) is a budget R095. Both Scubapro, in case that wasn't clear.

How important does the community feel it is to match the primary and backup regs? That would mean me buying another G260.

If you weren't doing staged decompression, I would stay with what you have. If you go doubles and decide to buy a matching pair, you can use the old regulators for deco/stage tanks. I've seen divers using cheap regulators for technical dives.

 

[Joneill]

I just posted a pic of a failure mode that straight up doesn't even exist with unbalanced 2nds.

So because you had a failure, no one should use a balanced second stage? Sure… lol

 

[PfcAJ]

So because you had a failure, no one should use a balanced second stage? Sure… lol

Mm, no. Read what I wrote.

For a BACKUP you want the most reliable option.

 

[ginti]

A simple, unbalanced backup is super reliable. This is what you want.

Keep your regs as is.

All of my backups are R190-type regs.

I am curious about what regs you use when you dive OC now, would you tell us?

View attachment 713575
R190 doesn't even have the possibility for this to be a problem.

I am very incompetent in this regard; my limited knowledge comes from Wikipedia, which doesn't explain the mechanism of balanced second stages (it mentions the concept, but not the details). Would you mind explaining what happened here?

 

[James79]

I am curious about what regs you use when you dive OC now, would you tell us?


I am very incompetent in this regard; my limited knowledge comes from Wikipedia, which doesn't explain the mechanism of balanced second stages (it mentions the concept, but not the details). Would you mind explaining what happened here?

In a balanced second, the soft seat has a small hole allowing pressure to pass through the stem of the poppet (the white piece in his picture) into the balance chamber (black piece in his picture). This puts an equal surface area on both sides of the ends of the poppet exposed to Intermediate Pressure (pressure provided by the first stage), thereby having the spring be the only significant force acting on it (holding it closed). With the break in the poppet stem @PfcAJ showed, the reg would end up effectively free flowing. A rare type of failure, but one that is impossible with an unbalanced second.

Respectfully,

James

 

[PfcAJ]

I am curious about what regs you use when you dive OC now, would you tell us?

I use a g250 primary and a r190 backup.

For the RB80, g250 primary, r380 backup (the slightly smaller size is appreciated as the whole thing gets busy with the BOV, necklace, primary, and sometimes a deployed deco bottle depending on what’s goin on). The inside of the BOV is also r190 internals and the rb80 injectors are r190 internals.

In addition to the excellent explanation from James above, the poppet has 2 small o rings, an extra spring, and a plastic balance chamber. IIRC g250HP models have a few extra pieces but I phased all those out of my gear because the g250 just breathes better imo. Any of those things can give you trouble. Even the lever can get dislodged.

I want my backup to work when I need it. The lower breathing characteristics of a simple unbalanced reg aren’t bad enough to forego the reliability gained.

 

[kelemvor]

I became convinced due to sb conversations a few years ago to go with "the same" secondary as primary. I replaced my R295 with an s600 to match my primary s600.

If you're getting your gear serviced every year or two by a pro, then I don't see the concern about more complicated parts being a priority. I'm paying for service either way, and they don't charge less for simpler regs at the shops I frequent.

Later, I moved away from that to an air2 for single tank diving. That's it's own contraversy right there (I'm a big fan). Clearly not DIR compliant.

I have been diving solo for a little while now as my wife can't currently dive. Therefore, I put together a pony and it's got the S600 on it now along with a valvulator type first stage.

 

[Joneill]

Mm, no. Read what I wrote.

For a BACKUP you want the most reliable option.

Ok… So because you had a failure, no one should use a balanced second stage as a backup. Got it… lol

 

[jjchang]

I became convinced due to sb conversations a few years ago to go with "the same" secondary as primary. I replaced my R295 with an s600 to match my primary s600.

If you're getting your gear serviced every year or two by a pro, then I don't see the concern about more complicated parts being a priority. I'm paying for service either way, and they don't charge less for simpler regs at the shops I frequent.

Later, I moved away from that to an air2 for single tank diving. That's it's own contraversy right there (I'm a big fan). Clearly not DIR compliant.

I have been diving solo for a little while now as my wife can't currently dive. Therefore, I put together a pony and it's got the S600 on it now along with a valvulator type first stage.

I think this is my first post on SB. This is not related to the subject discussed here. But, ...

About 3 years ago I personally experienced a tragic accident where a diver sucked his pony dry leaving his main tank full when he was found at the 300+ feet bottom. It is almost certain that when he jumped he was sucking his pony, which had a second stage identical to his other seconds, including the color of the hoses. Also, one contributing factor to this tragedy might be that his pony was filled with nitrox (not 100% sure because there was no air left). I guess that I would purposely set up my pony second differently from my main to the extent I can feel the difference right away when I suck it.