da aquamaster diaphragm

[Nemrod]

There were a number of articles and urban legends surrounding diaphragm first stages. Technically the failure mode is closed. Perhaps in the existence of the universe one such failure could have occurred somewhere in time (like supposedly in Australia on a Conshelf)? I am pretty sure the op has all the parts, his pin length was probably too short. The new diaphragm, did take a set, as they all do, and when it did the too short pin which barely was sufficient to open/offset the first stage when first installed was now therefore insufficient.

I just pulled down a gimme Conshelf, the first stage ambient diaphragm had quite the depression in it from the mushroom pin support.

If the pin length were too short after the first stage ambient diaphragm takes a set the static IP should still be lower than normal (as set) but the dynamic IP would be certainly low I should think.

N

 

[John C. Ratliff]

Those regulators belong on the wall as a memory of bygone days. I never had the described problem with my aquamasters in 15 years of using them in the Navy. Aftermarket parts and makeshift parts will kill someone. When the single hose US Divers Conshelf came out they were much less problems and I still use the US Divers single hose with the metal second stage. Just my opinion not knocking the old double hose so easy to exhale and just lay back to get an easy inhale. Yes I got one on the wall Be careful.

Sealark,

First, as an old Air Force guy who went through the Underwater Swimmers School in Key West in 1967, I appreciate your service.

We we have been using aftermarket parts for the Aquamaster for many years now, with great success. It shouldn't be the aftermarket parts that are the problem here.

Duckbill, if all the parts are present on this regulator, and it malfunctioned in the described manner after having worked for three months, a diaphragm "set" should not cause this problem. That is a movement of less than an eighth inch. The interstate pressure when this problem developed was zero psig, as described. Normal interstate pressure is at least 110 psig. The HP diaphragm did not become unset from the spring retainer (part #1000-05), as that would have been noticed. The only way I can see to get this result would be to unscrew the adjusting screw (part #1000-06) to remove pressure from the second stage. If the pin is too short, it is not in specs for this regulator. If someone shortened the pin, it would not function for 3 months, then stop functioning. I am curious as to what interstate pressure the regulator was set to initially? If extremely low interstate pressure was set, perhaps this is possible, but then simply screwing in the adjusting "screw" (US Divers Company name for the Allen wrench-adjusting nut) would give an interstate pressure and the ability to remove the regulator from the tank.

SeaRat