Regulator reliability?

[Greg Barlow]

They really do not come any more reliable than a MK 2.

It is a very simple design with 1 moving part and only 2 dynamic o-rings both of which are only subject to intermdiate pressure air. The TIS system also works extremely well in the Mk2 and it makes a great ice diving reg.

The design also has evolutionary roots going back to the mid 60's so any bugs have long since been worked out of the design.

There is not much to go wrong on a Mk 2 and with proper care and regular service it should last a minimum of 20-30 years even with a lot of dives on it. Worst case you'll have to replace the cap on it or perhaps the main body if enough wear occurs to compromise the seal of the dynamic o-rings that travel in those areas. But given that only IP air is involved, that is rarely ever an issue.

Personally, I don't think regulator design has advanced much at all since the mid-80s in terms of flow capacity and inhalation resistance. Plastic cases have become standard, but the main advantage with them has been lower producton cost. The weight advantage is minor and secondary to mouthpiece design and LP hose lenght in terms of the effect on comfort. They are less durable and cracked cases were never an issue with brass second stages but are rather common with plastic cases.

First stages have gotten lighter and titanium is used a lot, but it has created more problems than it has solved interms of nitrox compatibility. And the weight savings is just not worth the money.

So the main advantages of modern regs tend to be marketing hype for the most part and most don not really do the job any better than many quality regs made 10-20 years ago.

DA,

When it comes to regs there isn't much that we differ on. Heck, I even own and dive with a rebuilt DA Aquamaster (among my several other functioning vintage regs).

Greg Barlow

 

[Tim Wong]

Would the same reliability of a downstream demand valve 2nd stage also apply to the pilot valve 2nd stage? Just wondering.

 

[DA Aquamaster]

I am not aware of any true pilot valve regs still in production or having been produced since SP discontinued it's Pilot second stage. The Pilot was hard to service and hard to adjust so it's hard to separate problems from the design itself from problems due to poor/improper adjustment.

The Scubapro D300/350/400 series used a center balanced valve design that was very reliable. With the move to plastic orifices however in the late 90's adjustment for peak performance became more difficult and more critical and it was not uncommon for a slight freeflow to develop after several dives were done following annual service which would require a trip to the tech for readjustment. On the other hand the center balanced valve design in the D300. D350 and D400 is very relaible in cold water and the light spring pressure inherent in the design tends to make it very long lived with regard to required (versus recommended) service.

In general the more common balanced poppet second stage designs are also very relaible even though they are generally more complex with a moving poppet and 1 or 2 more dynamic o-rings.

It is rare for a second stage to fail in any way other than to develop a slight freeflow as the soft seat ages. I have however noted that some plastic cased second stages are more prone to forming ice inside them due to poor heat transfer. This can, in the extreme, cause the lever to be blocked and result in the second stage failing closed.

The advantage of a downstream design like an R190 is ease of service. There is very little that can go wrong in the field that cannot be fixed very quickly by flipping the seat over. This is a relatively simple procedure and can be done with very little disassembly of the regulator itself and with no new parts required.

 

[ChrisA]

I'm also looking to buy a new regulator to use as both a backup and as a pony bottle/bailout reg. With luck, I hope never to have to use it. What I'm finding is that price is NOT related to reliability. I'm looking at the Aqualung "Calypso". The first stage is a balanced piston and the second stage is about as simple as possable. Comes with lifetime warenty and the price at the local shop is $110. All that advice we keep reading to "spend as much as you can on the reg because your life depends on it" may m not be exactly right. Even some low priced regs are very reliable. That said I don't think I'd buy a "Calypso" as my primary reg. my Apeks reg breaths better at depth.

Is there any reason NOT to use a "Calypso" for my intended purpose?

I got to thinking about backup equipment when a couple weeks ago my buddy and I are on a two day live aboard trip and he jumps off the boat 8 feet into the water with part of his gear caught on the boat's rail and rips an end fiiting of a hose. Short dive but lots of noise and bubbles. Had to go begging for repair parts.

....The advantage of a downstream design like an R190 is ease of service. There is very little that can go wrong in the field that cannot be fixed very quickly by flipping the seat over. This is a relatively simple procedure and can be done with very little disassembly of the regulator itself and with no new parts required.

 

[DA Aquamaster]

I still use SP Mk 3's for my deco regs despite having several other high performance regs in the closet as in many ways the small, simple, reliable, and unbalanced MK 3 is ideal for the task.

An unbalanced piston reg like the calypso could make a good backup reg provided you did not exceed its performance limitations.

On my normal double tank rig, my backup reg is the same model MK 20 D400 as my primary and in general in a technical diving situation it is always a good idea to use a backup with performance equal to your primary.

So a Calypso could work as a backup but only if you were limiting yourself to dives above 100-130 ft. The good news is that if you start diving deeper than this, you will most likely be (and should be) deco and advanced nitrox trained and in need of a deco reg anyway, so you will still have need for your calypso.