How do regulators fail?

[Cthippo]

I will probably need an asbestos wetsuit for this, but...

My Palantic regs are a year old now and no one in this hemisphere services them. I can get rebuild kits cheaply online, but rebuilding a reg is not something I want to try without some actual in-person training and guidance. They only have less than 20 dives on them so I expect I can push it a bit longer, but that leads to my question.

When a reg fails from lack of service, what is the failure mode and what are the warning signs?

 

[johndiver999]

You want to buy an intermediate pressure gauge. This allows you to confirm the first stage is dropping the tank pressure down properly. You can check that the regulator does not freeflow or release bubbles by pressurinzing it in the water. If it doesn't leak anywhere, has the right IP pressure, and it is still easy to breath, and there are no obvious problems with cracking hoses etc., then it will probably continue to work (for quite a while- especially if you soak it in freshwater for 20 minutes before putting it away).

 

[Zef]

Since you can obtain rebuild kits, I recommend contacting @rsingler to discuss when his next regulator maintenance course is. In the meantime, purchase an IP gauge and connect to the LP hose that goes from your 1st stage to your power inflator. It would help to research/know the proper IP for your 1st stage, but if your reg set was working normally in the past and the IP gauge needle does not settle (lock up) on a specific value and instead continues to climb/creep upwards, then there is something amiss that needs to be addressed....Rsingler's course will help you zero in on what is amiss and what should be done about it.

-Z

 

[lowwall]

Regs should last years if you rinse them carefully, let them dry and store them out of the sun and heat.

The usual failure mode for a second stage is the seat taking a deep enough groove that it won't fully seal. You'll hear a hiss or see bubbles if you hold it underwater. The fix is a new seat, although with some seconds you can flip the seat over and keep using it. If the second is adjustable, you might be able to adjust it out for a while.

Failure mode for first stage depends somewhat if it's a piston or diaphragm. But either way, you can detect it early with the use of a $15 IP gauge.

See this thread for how to check functioning of your regs: Regulator Inspection and Checklist (Rev-8) . If they pass and you are taking care of them, then I'd be comfortable continuing to use them no matter how long it's been since they were serviced.

A big disadvantage of letting service go too long is that it will make any eventual service difficult because threads will get stuck with corrosion or salt crystals or silt. But if you are planning on replacing the reg when it develops problems instead of fixing it, that's probably not a consideration.

 

[Ghost95]

In my experience, most regulators mode of failure is to free flow or leak. This also happens after a fresh service if the seats weren't broken in before the final adjustment.

I recall there are a couple designs, upstream seconds I believe, that can fail to a closed position. I've never had experience with those regulations though. Everything I've dealt with will leak and free flow.

 

[Nemrod]

SCUBA regulators mostly fail when they have been serviced when they do not need to be serviced.

 

[Eric Sedletzky]

Most regulators IMO get serviced way too often for no other reason then to keep the service bench at the shop busy. Every time your reg gets torn down and molested by someone you don’t know the more wear and tear happens. More damage gets caused to regulators by heavy handed techs than by any other cause. Years ago when I first got into diving they told me that my Scubapro regs had to come in once a year to be serviced regardless of use because if you don’t you’ll die. They said “it’s worse for regs to just sit around”. So I bought into it as long as I got FPFL, but then that ended and so did me bringing it in every year. And you know what happened? Not a damn thing!
Then somehow, *magically*, Scubapro declared that regs now only needed to be serviced every two years or you’ll die, but I was long gone by then.
I think my record on my MK/20 for stalling service was 6-7 years and it made no difference.

Then I discovered Scubaboard with all the knowledge on DIY, debunking fallacies, etc.
I also learned some proper rinsing and care techniques that make all the difference in the world. I never looked back.
Just keep an eye on the IP and keep diving it.
“If it ain’t broke don’t fix it”

 

[Nemrod]

I will answer on a more serious note. And some of these things may not mean a regulator needs service, it may only need a simple adjustment or part replacement.

1. IP out of specification (use a IP pressure gage), 125 to 145 are typical ranges
2. IP rising when regulator is under pressure, second stage may relieve
3. Regulator leaking at first stage or second stage, IP will fall when tank valve is shut off, watch the spg
4. Cracking effort too light or too high, out of specification (use a Magnehelic or the kitchen sink to approximate inches of water, most single hose second stages should crack at around 1.5 inches of water give or take
5. General condition, broken or missing parts, visible corrosion
6. Hoses cracked, split, frayed, bulging especially around fittings where flexed

Always test dive a regulator when returned from service, preferably in a pool, before taking on a trip so that the function can be verified after the (new) seats take a set.

A professional shop, IMO, should return all replaced parts, provide a before and after IP and cracking effort compared to factory specification, bench test/flow and cycle the regulator and then give the customer a printout detailing these things including how many times the regulator was cycled and finally a leak check.

 

[rsingler]

One cautionary note to the "if it ain't broke, don't fix it" mantra...

I have a SPEC-booted Scubapro Mk10 that I just took to Cayman Brac for a week of diving that hasn't been serviced in over ten years.

It started here: thread DIY SPEC Boot .
IP locks up crisply in the high 120's and has never budged.

But I lied...
Every year, I remove, clean and replace the yoke bolt. The rest of the mechanism has never been touched.
Why do I do this?

It used to be that manufacturers used a HP o-ring at the collar of the bolt threads:

But they had a higher incidence of extrusion, so most mfrs have gone to end o-rings at the bottom of the DIN or Yoke bolt.

The problem with the change is that the collar o-rings protected the bolt threads from salt water that otherwise percolates in under ambient pressure on a dive. That salt never gets rinsed out, and gradually causes verdigris corrosion which locks the bolt to the reg body. In contrast, an end o-ring offers no such protection.

I just recently serviced three Poseidon XStream sets for a customer who "got them off eBay" for a steal. And indeed, they all locked up nicely within spec. The XStream is the best diaphragm design in the world, IMO.
But he ended up spending an extra $90 on two new DIN bolts because I literally had to deface them with a pipe wrench to disassemble them from the reg body. The U/S didn't work; the freezer didn't work; I bent my custom wrench on the thin flats of the bolts (as well as spalling the brass). Finally, they sat for 4 days after drippng Aero-Kroil into the threads, and a pipe wrench did the trick.
Poseidon switched from a collared o-ring on the 2960, to an end o-ring on the XStream. Arrgh!

So I lied about my Mk10. The internals haven't been serviced in 10 years, but the bolt comes off every year.

If it ain't broke, maybe don't fix it. Except the yoke or DIN bolt. Service it every year, because you can't see that it really needs it.

 

[L13]

One cautionary note to the "if it ain't broke, don't fix it" mantra...

I have a SPEC-booted Scubapro Mk10 that I just took to Cayman Brac for a week of diving that hasn't been serviced in over ten years.
View attachment 798434
It started here: thread DIY SPEC Boot .
IP locks up crisply in the high 120's and has never budged.

But I lied...
Every year, I remove, clean and replace the yoke bolt. The rest of the mechanism has never been touched.
Why do I do this?

It used to be that manufacturers used a HP o-ring at the collar of the bolt threads:
View attachment 798426
But they had a higher incidence of extrusion, so most mfrs have gone to end o-rings at the bottom of the DIN or Yoke bolt.
View attachment 798427
The problem with the change is that the collar o-rings protected the bolt threads from salt water that otherwise percolates in under ambient pressure on a dive. That salt never gets rinsed out, and gradually causes verdigris corrosion which locks the bolt to the reg body. In contrast, an end o-ring offers no such protection.

I just recently serviced three Poseidon XStream sets for a customer who "got them off eBay" for a steal. And indeed, they all locked up nicely within spec. The XStream is the best diaphragm design in the world, IMO.
But he ended up spending an extra $90 on two new DIN bolts because I literally had to deface them with a pipe wrench to disassemble them from the reg body. The U/S didn't work; the freezer didn't work; I bent my custom wrench on the thin flats of the bolts (as well as spalling the brass). Finally, they sat for 4 days after drippng Aero-Kroil into the threads, and a pipe wrench did the trick.
Poseidon switched from a collared o-ring on the 2960, to an end o-ring on the XStream. Arrgh!

So I lied about my Mk10. The internals haven't been serviced in 10 years, but the bolt comes off every year.

If it ain't broke, maybe don't fix it. Except the yoke or DIN bolt. Service it every year, because you can't see that it really needs it.

I wish they would do both o-rings. That would solve both problems. and cost less than $0.25 more.