Questions for experienced regulator service technicians.

[Mcarlson]

What is the most common point of failure for regulators? I'm not asking about regulators that have been subject to severe neglect, but ordinary use with basic maintenance.

If you could double the useful life of one component of either the first or second stage, which one would you pick and how would that impact the service interval?


Does the IP of a balanced piston 1st stage tend to creep up or down between service/adjustment?


Are there any conditions or practices that greatly accelerate or prevent wear, other than thorough rinsing with fresh water after use?


I'm not trying to re-open the optimal service interval discussion, just get some data beyond my personal experience and educated guesses. I realize that answers may be brand or model specific. If you have specific knowledge of Scubapro Mark 10/G250B I'd be very interested to hear that too (my regulator is 25+ years old with hundreds of dives and never the slightest problem.)

 

[halocline]

What is the most common point of failure for regulators? I'm not asking about regulators that have been subject to severe neglect, but ordinary use with basic maintenance.

If you could double the useful life of one component of either the first or second stage, which one would you pick and how would that impact the service interval?


Does the IP of a balanced piston 1st stage tend to creep up or down between service/adjustment?


Are there any conditions or practices that greatly accelerate or prevent wear, other than thorough rinsing with fresh water after use?


I'm not trying to re-open the optimal service interval discussion, just get some data beyond my personal experience and educated guesses. I realize that answers may be brand or model specific. If you have specific knowledge of Scubapro Mark 10/G250B I'd be very interested to hear that too (my regulator is 25+ years old with hundreds of dives and never the slightest problem.)

1. It depends what you mean exactly by 'failure' but the most common item to wear out first on most regulators is the 2nd stage seat, this usually causes a slight freeflow (which can often be adjusted out) and/or an increase in cracking effort. After the 2nd stage seat, my best guess is that dirty filters and some 1st stage o-rings would be the next most common trouble spot, although actual 'failure' is almost always a leak, and that can happen in places like the 2nd stage exhaust valve or the 1st stage o-rings that seal the yoke/DIN fitting.

2. I think the most effective way of extending the service interval would be to double the useful life of the 2nd stage seat; this is why there are many 'seat saver' features that reduce or remove pressure between the seat and orifice when the reg is not pressurized. Next would be to environmentally seal the 1st stage so that sea water never enters the ambient chamber.

3. IP tends to creep up with extended use. However, I have MK5s that are going on several years and hundreds of dives without any signs of creep at all. But, wear in the HP seat and piston edge will always cause IP to go up, not down. There is some discussion about the wearing properties of the main spring; over decades this spring can reportedly lose some elasticity, causing IP to either wander around seemingly unpredictably, get lower (due to less stiffness in the spring) or go up (due to more stiffness in the spring) depending on who you talk to. None of my MK5s or MK10s have ever had a problem with the spring. I have had a few problems with old doublehose mainsprings, mostly in their inability to hold a steady, high IP. The crowd over at vintagedoublehose has sourced some new springs for the USD doublehoses that work very well.

4. I think thorough soaking in fresh water, then drying the regulator by putting it on a tank and purging some air through is a good practice. I try to relieve as much pressure on the 2nd stage seats as possible during storage, and I don't think it's a good idea to hang regs up by the hoses for storage. I also think UV can deteriorate some compounds fairly quickly. I have heard from some instructors that the chlorine in pools is very tough on regulators.

I have lots of experience with MK10s and the G250; although you mentioned "G250B"; you might have meant the G200B, which is a G250 without the adjusting knob. I have one of those too; I rarely use it but it's a very nice 2nd stage. What specific questions do you have about those? IMO the MK10 is a great classic 1st stage although mine tend to creep more between service than my MK5s. That said, I have a pair of sealed (packed with PTFE grease) MK10s that I rebuilt at least 4 years ago and they perform as good as new. I don't use those as often because they're set up for doubles.

 

[Mcarlson]

Thanks, halocline!

My 2nd stage is definitely a G250 - it has the adjustment and venturi. I remember the "b" designation when I bought it, but never sure what it meant. I know Scubapro sometimes designates minor changes with an "a" or "b" but I'm not sure.

You correctly guessed that my inquiry was based in the 'seat saving' features on the Atomic regulators.

Thanks again!

 

[halocline]

To prolong the seat in your G250, make sure the breathing resistance knob is all the way out for storage. You can also partially depress the purge button and hold it in place with something; SP had a key for this at some point. Awap knows more about that than I do. I'm not sure its necessary.

The atomic seat saver actually separates the seat from the orifice during storage, but it also means that you can't soak the regulator unpressurized. That would be a deal breaker for me. Since I've had G250s and balanced/adjustables sit for years and barely take a set in the seat, I personally don't have a need for the kind of seat saver that atomic uses.

 

[tbone1004]

1. seats, 2nd stage seat then first stage HP seat depending * I dive Poseidons most of the time so don't have a "seat" per se and in that case the second stage issues are usually the condom valve inserts*

2. see #1. Like most technical/cave divers I only service mine when they ask for it, so it would be nice to extend the interval, but they are usually due for a hot date with the ultrasonic before something actually "fails". I always take mine apart and clean them after the summer ocean season in prep for the rest of the year in the caves.

3. not a lot of piston experience because I don't like them, but they tend to go up with the exception of the spring wear mentioned above.

4. sealing or opening them wide open is the best solution. For sealing this is why I don't like pistons, and Poseidon MK3 is wide open so thorough rinsing is quite easy. Normal looking first stages tend to hold water and that's bad and generally causes all sorts of problems.