US Divers Conshelf 21 service?

[thbcthomas]

IP is one important check and that looks good. Check for pressure and vacuum leaks and pull a few connections to peek inside and look at the condition of a few o-rings. I expect I would be diving them until they gave me reason to have them serviced.

It does not really matter when theybwere last services. What matters is their performance and condition NOW.

Thanks for the advice.
Ok thanks for the advice. Looks like they are good to go.

 

[tbone1004]

I'd dive them. IP locks up, if the second stages hold a vacuum and breathe well, and nothing leaks, I'd dive them today no problem

 

[tech3324]

I seem to recall that the Conshelf received an upgraded HP seat at some point in time. I took one of mine in for service and the tech commented that it needed the "newer" HP seat, which he did. Does anyone recall specifically or am I mistaken on that?

But that could be a reason to service earlier.

 

[buddhasummer]

I can't answer your specific question but there was/is nothing wrong with older seats.

To the OP, if it works, it works, if you get it serviced it'll still work. I'd dive it as is.

 

[sealark]

Ive been diving and servicing conshelves for 40 years. Never seen one stop working. What happens is they will start creaping and freeflow a small amount. Use the tested one you have if those figures you supplied did not creap after sitting pressurised for a few minutes. Also they are easy to rebuild yourself. I just yesterday had one creap and freeflow. I overhauled the first stage in 30 minutes. The secong stages usually go about 1 out of 3 or 4 1st stage overhauls.

 

[Fishpie]

1st stage.
The latest seat that I'm aware of has been around for 10 plus years and is the same seat that is used in all US Divers/AquaLung diaphragm regulators.....it is nickel/silver with a royal blue seat material.
Previous seats were copper/brass with black rubber seating material.
There were also some white/yellow and light blue seats with seating material covering all the metal part including the shaft.....these are the only ones I will replace before needed(found quite commonly in SE3's and 22's)
Earliest is the "military" seat with small diameter rubber seating material (metal part is copper/brass)
(All 1st stages can use any era seat)

Unbalanced 2nd stage.
Never had to replace seat in any 2nd stage (with the "new" large diameter exhaust valve....newer style 2nd stage).
Seen them in grey, red and black ..... seats (not exhaust valves).

 

[buddhasummer]

I have some military new stock ones and the exhaust valves are yellow, I've also seen clear. I read the DiveRite exhaust valves work so bought some to try. I'll post back if anyone's interested.

 

[buddhasummer]

What is the size of the "new" large valve? 29mm? Cheers.

 

[buddhasummer]

Yes, 29mm, answered my own question.

 

[thbcthomas]

I have some military new stock ones and the exhaust valves are yellow, I've also seen clear. I read the DiveRite exhaust valves work so bought some to try. I'll post back if anyone's interested.

I am interested if they work. Looking for all the info i can get as i am going to start servicing them myself. I have a couple of mk10s laying around that i will use as practice.