DIR- GUE Regulator Set Recommendations

[halocline]

Parts for life is just a scheme to drive business to dealers. SP had an annual service interval for DECADES then one day it was every two years. What changed? Nothing. They’ve always been reliable enough to go multiple years between service, but the model was to offer free parts annually so you’d pay shops for reg service annually.

Exactly.

 

[Wstern5]

SP mk10/15/20/25 are all great 1st stages. If you need a sealed reg for cold water mk17, but the hose routing isn’t as clean.

What temperature would you want to start using Mk17?

 

[lexvil]

I'm not fond of the MK11, especially for technical diving where you might want a turret or end port depending on your configuration. I also choose to use MK5/10s rather than MK25s because of parts availability. To service a MK5/10, you only need the SP seat; three of them come in a service kit and usually two of the three will work for an individual regulator. There are also perfectly acceptable aftermarket seats available. These seats are cheap and readily available. The rest of the kit is simply o-rings that you can get at any supplier, usually fresher and higher quality (if you want) than what comes in OEM kits.

The MK25 seat is really only available from SP or some grey market source, the kits are expensive, and they include bushings that are impossible to find elsewhere. So it's simply more expensive to service MK25s than it is MK5/10s. There's no way around that.

In terms of other parts, really the only one that ever gets replaced occasionally is the piston, either due to damage on the knife edge (which is sometimes repairable) or corrosion on the piston head. I see NOS MK5 and 10 pistons fairly regularly for sale, and it's often cheap enough just to buy another 1st stage. The MK25 piston, while it works really well, has a design flaw; it has an internal o-ring that is officially not user-replaceable. This o-ring will wear out and the piston will leak. The only solution is a new composite piston, which generally costs more at retail than a MK5/10 costs on the used market.

The only rub with using MK5s is the DIN retainer; it's not the universal retainer, and it is hard to find. A friend (long time poster on this forum who no longer is a member) was able to make the universal retainer work in MK5s with a 2mm thick brass washer. I haven't tried it because I found a few MK5 retainers.

Then there is a legitimate issue with IP rise and HP tanks in the MK10. But, if you use a good, fresh, polyurethane 90 duro o-ring on the piston shaft, it holds pretty well, and I have found that the MK11 has an IP curve worse than the MK10, although it goes in the other direction. Try a MK11 sometime at 3500 PSI and check it again at 300, you'll find the IP about 15 PSI higher at 300. It's not good. MK10s tend to rise 7-10PSI from 300 to 3000 (or just a bit above) and then, depending on the o-ring, go up more with HP tanks. I don't know how mch it matters on an actual dive, but it kind of bugs me because I'm a nerd.

Isn’t everything for the MK 5 essentially “gray” market? Pistons are a finite commodity. The MK 5 is a great regulator but I find the improvements incorporated into the 25 along with basic ease of parts availability worldwide a better plan. The OP stated he was looking for a stage regulator, the MK 11 is truly great for such applications but it’s also a good way to extend the usable life of any old regulator type.

 

[PfcAJ]

What temperature would you want to start using Mk17?

Cold.

idk like below 40? Not really in my wheelhouse so I’d have to figure that out. There are cold water bros on here that will have a better take on it than me.

 

[PfcAJ]

Keep an eye on the IP of those. I know of several that would creep upwards of 200psi before locking, all tied back to the monel pistons.

Any issues with the non monel models?

 

[kensuf]

I don't think so. A guy I know that's a wrench up in Georgia told me he replaced the monel pistons with standard ones and that seemed to solve the issues.

 

[halocline]

Isn’t everything for the MK 5 essentially “gray” market? Pistons are a finite commodity.

The kits are still sold by SP, and again, the seat is the only part other than o-rings for a rebuild. As for the piston, I have replaced exactly one MK5 piston in my life, out of at least 20 that I've owned or worked on for others. They really hold up. And the last time I saw a price for a MK25 composite piston (several years ago) it was $70. You could probably find 2 MK5s or MK7s for that price with working pistons.

MK25s are fine regulators, and for someone who is taking them to a SP dealer for service, they are very practical. But kits are expensive, probably about $40 now. I rebuild my MK5s for a couple of dollars, use them cave diving for years, and then spend another $2-3 dollars on a rebuild.

My comments about the MK11 are just my personal opinion, based on my experience with a few of them. I personally would not buy a new 1st stage that has a 15PSI swing over the supply range, while being sold as balanced. I would rather use a MK2 on a stage or deco bottle; the IP swing is about the same, (in the opposite direction) and they are cheaper to buy and service, easier to O2 clean, and very likely more tolerant of being flooded than a balanced diaphragm reg.

 

[lexvil]

The kits are still sold by SP, and again, the seat is the only part other than o-rings for a rebuild. As for the piston, I have replaced exactly one MK5 piston in my life, out of at least 20 that I've owned or worked on for others. They really hold up. And the last time I saw a price for a MK25 composite piston (several years ago) it was $70. You could probably find 2 MK5s or MK7s for that price with working pistons.

MK25s are fine regulators, and for someone who is taking them to a SP dealer for service, they are very practical. But kits are expensive, probably about $40 now. I rebuild my MK5s for a couple of dollars, use them cave diving for years, and then spend another $2-3 dollars on a rebuild.

My comments about the MK11 are just my personal opinion, based on my experience with a few of them. I personally would not buy a new 1st stage that has a 15PSI swing over the supply range, while being sold as balanced. I would rather use a MK2 on a stage or deco bottle; the IP swing is about the same, (in the opposite direction) and they are cheaper to buy and service, easier to O2 clean, and very likely more tolerant of being flooded than a balanced diaphragm reg.

So the same supply issue with either, I don’t like the hoops we have to jump through for parts but I find the newer Regs easier to obtain since there are more shops likely to have a 25 kit than a 5, a MK 2 is alway a great choice for stage application. Not all MK 11’s (or 17’s for that matter) have the wide swing but some do, I agree that the mk2 is probably the best choice for this application.

 

[halocline]

So the same supply issue with either,

For me that's not the case, because it's much less expensive and easier to find MK5/10 kits from sources other than SP dealers. I like MK20s, for example, especially ones with the early, all steel piston. But I don't keep them or use them because I don't want to pay a fortune for rebuild kits.

For someone who's only option is getting parts from a SP dealer, and needs a variety of parts, not just kits, then I think your is true. But since what I really need is HP seats only, it's both cheaper and easier to keep my MK5s and 10s going than it would be MK20/25s. In fact, that is the main reason I use the older balanced piston regs. I love my MK15s and will use them until I run out of HP seats, then retire them.

If I had a reliable source of MK20/25 kits at dealer cost, I'd probably use those.

 

[garyh]

Hp seat failures is the biggest. My other two big annoyances are the hand wheel on the din valve sucks. When my hand is wet and cold it’s a pain in the rear to tighten or looen the reg from the valve. It sounds really dumb, but I’ve got quite a few friends that tell me it secretly annoys them as well. Another thing is how crappy their din threads feed onto tank threads. Every sp and other brand I’ve had, the male din just screws right into the valve easily. Rarely any cross threading. My wife and I have 8 apeks firsts. Every single one of them are a pain in the ass to screw onto the valve. You’re guaranteed at least one attempt at putting your reg on your tank it’s going to try and crossthread and you’re going to have to back it up amd restart. I’ve asked others that have apeks and they notice the same things.
The apeks are good regs, but there’s just annoyances about them that turn me off to them. The main one being the number of hp seat failures I’ve had. And the fact that I don’t think apeks still acknowledged they exist, even though they changed their service kit after all of the complaints of failures.

solid regs but +1 on the hand wheel sucks!