Fail open? Not always

[redacted]

... I had 20 dives on that reg since the service. The only thing I noticed was the adj. felt harder to turn than usual. It wasn't an upgrade it was regular service done by someone I'd never used before and wouldn't use again. The guy that found the problem was the guy that has been working on my MK5 since he was a teen, his father taught him. His dad was one of the 1st scubapro dealers in NE.

That could indicate a spring under higher than normal tension. Would be entirely compatible with the subsequent failure.

 

[halocline]

You've got it right except for the tech. The son of my friend FOUND the problem after I brought the reg to him. The tech that CAUSED the problem was someone I'd never used before and wouldn't use again.

Got it, sorry about the mix up! I'm still pretty confident that your problem involved a lever mis-match. The heavier unbalanced spring, if it's in there, would make the reg harder to breathe, but I can't imagine it would ever cause the reg to 'fail closed'. However, that's exactly what would happen if the lever came off the tabs on the poppet. Maybe the heavy spring pushed the poppet so much that in conjunction with the air pressure from the balance chamber it literally pushed the poppet tabs off the feet of the lever.

The truly strange thing about this is that if you had regular service on this reg for the last several years, you would have had either the new duro poppet or the s-wing poppet. If the heavy spring was in there, lets assume it was the duro poppet. Well, that has a replaceable seat, and rebuilding the reg requires only the seat replacement, not the poppet. So, the new guy probably should not have changed the poppet anyway.

 

[DA Aquamaster]

I have this occur once on a 109 I worked on. It tested well, but failed on the customer mid dive. On inspecting the reg later, the only possible cause I could come up with was that the legs on the lever had lost some tension and were able to spread a bit and allow the poppet to jump past them.

In terms of new poppets and old levers, I have noted that some R109s from the late 1960's have levers with tabs that are too wide for the current poppets (either S-wing or unbalanced G200 poppets). If you don't replace the lever, it will bind on the poppet and breathe like crap.

Putting an R109 spring behind a balanced poppet will greatly increase the compression of the spring (as the balance chamber is also in the stack) and then for two reasons greatly increase the force needed to lift the poppet. I am not sure it would even breathe, and it would be a bitch to assemble so it would be a hard mistake to make, but if this occurred, I could definitely see the spring forcing the poppet past the tabs on the lever so failure would be near certain in short order.

 

[Akimbo]

I was using a side exhaust regulator and noticed that inhalation resistance was increasing. After checking my SPG, I took it out of my mouth for inspection. The screw retaining ring that held the hose and valve assembly to the housing was loose and allowed the demand lever to pull away from the diaphragm. I tightened it back down and continued the dive.

Is this a regulator fault? Was AfterDark's? Is it a regulator fault if the first stage inlet filer is clogged? I suppose you have to include a diaphragm retaining ring failure due to improper installation, and an IP hose failure as well. All five cause supply failure. I often wonder if the industry wouldn’t be better off sending regulators back to the factory for service than depending on dive shops. No matter how diligent, no dive shop has the resources and experience that can compete with the manufacturer.

I am not implying in any way that there are not a lot of good regulator repair techs, but we all know that there are a lot more that are not so good.

 

[halocline]

I often wonder if the industry wouldn’t be better off sending regulators back to the factory for service than depending on dive shops. No matter how diligent, no dive shop has the resources and experience that can compete with the manufacturer.

I am not implying in any way that there are not a lot of good regulator repair techs, but we all know that there are a lot more that are not so good.

Regulator service does not take a great deal of resources, machinery, or even specialized knowledge. All it takes is simple attention to detail and the willingness to spend time checking your work.

Sending regs back to the factory is not the answer for me; I go the other way and take responsibility for my own regulator service.

The fact that there are so many stories from people that have had regulator failure on a dive is confirmation that this whole 'life support' crap is merely an industry attempt at customer control. If regs were 'life support' then we would not be reading stories from divers that have had reg failure; we'd be reading their obituaries.

To me it's especially insidious when the dive shop is responsible for both teaching the class that emphasizes buddy system, air sharing, and other ways of dealing with regulator failure, and telling the customer that their lives depend on their regs.

 

[Wayward Son]

this seems to be a case where the failure is due to service using parts that were incorrect for the stage, or at least an incorrect combination of parts.

 

[Akimbo]

Regulator service does not take a great deal of resources, machinery, or even specialized knowledge. All it takes is simple attention to detail and the willingness to spend time checking your work.

Sending regs back to the factory is not the answer for me; I go the other way and take responsibility for my own regulator service.

The fact that there are so many stories from people that have had regulator failure on a dive is confirmation that this whole 'life support' crap is merely an industry attempt at customer control. If regs were 'life support' then we would not be reading stories from divers that have had reg failure; we'd be reading their obituaries.

To me it's especially insidious when the dive shop is responsible for both teaching the class that emphasizes buddy system, air sharing, and other ways of dealing with regulator failure, and telling the customer that their lives depend on their regs.

I agree. My musing was more an issue of how the industry could function more effectively. We have all seen repair benches that look like they were repairing their outboard on it and "technicians" who were not especially qualified or attentive.

I also do my own regulator repair, but everyone does not have the interest or resources. Dive shops are usually pretty good at repairing regulators in their rental fleet, but anything else can be hit or miss. It is more a question of efficient operations. It costs money to train people and keep inventory. Believe me, I am one of the last people to support the "regulator = life support" argument.

 

[AfterDark]

IIs this a regulator fault? Was AfterDark's? Is it a regulator fault if the first stage inlet filer is clogged? I suppose you have to include a diaphragm retaining ring failure due to improper installation, and an IP hose failure as well. All five cause supply failure. I often wonder if the industry wouldn’t be better off sending regulators back to the factory for service than depending on dive shops. No matter how diligent, no dive shop has the resources and experience that can compete with the manufacturer..

In my OP I stated it wasn't the regs fault. Forty years diving that reg NEVER a problem, not even a slight problem.

The fault was mine, for bringing it to someone that I've never used before. I was in a hurry to start diving, the LDS family owned, that has been maintaining that reg since day 1 is now 75 miles away from me so I took it to a LDS nearby that has been around for decades. Whoever worked on it dropped the ball. They will not get a second chance and 150 miles round trip twice is worth the piece of mind to know my reg is not F###UP'ed!

 

[Akimbo]

In my OP I stated it wasn't the regs fault. Forty years diving that reg NEVER a problem, not even a slight problem.

The fault was mine, for bringing it to someone that I've never used before. I was in a hurry to start diving, the LDS family owned, that has been maintaining that reg since day 1 is now 75 miles away from me so I took it to a LDS nearby that has been around for decades. Whoever worked on it dropped the ball. They will not get a second chance and 150 miles round trip twice is worth the piece of mind to know my reg is not F###UP'ed!

My question about "fault" was intended to indicate that the failure you described was no more the regulator's fault than a clogged filter or warn hose would be. Sorry if it didn't come across that way. To be fair to you, there would be a first time whenever you use a new person for a repair. Hopefully, your LDS 75 miles away will be around as long as you need them.

Your story is a lesson to people who design just about anything though. It is very difficult, but designing parts that are nearly identical is a nightmare for service, inventory, and the good name of the product. It can’t always be helped, but anyone who has gone to the hardware store to look for plumbing parts can appreciate the problem. It is in no way an excuse for your experience, just an undesirable design feature.