tripplec wrote:swimjim wrote: If your into piston regs, go with Sherwood and their dry bleed system. They are good cold water regs and they deliver.
jim
So to go back to an old topic, are sealed piston regs more problematic than sealed diaphragm? The check valve in the piston and relief valve in the body to me look like more things moving. Moving parts means more to maintain or replace in my opinion. But thats just looking at pictures. What are the thoughts of people working on them? Which is better in cold,if any difference?
To the best of my recollection, the piston does not have any moving parts on it. The device you mention is not a check valve, but appears to be a porous metallic (I think) metering device that is calibrated to pass a tiny volume of air. Anyway, it is pressed into place and does not move. The relief valve in the body is one piece rubber construction, and serves both as the relief valve to pass that metered air, and a check valve to prevent water from entering in case the air is turned off or depleted. Probably not much to worry about if the rubber is in good shape and the proper amount of air is passing out of the reg. I don't recall the time period, but seems like the overhaul specs called for holding a shot glass inverted over the first stage while underwater. It was to fill with air within some set period of time that I don't recall. So add a shot glass to your tool kit, it may also come in handy after the dive.
Although I don't personally care for the Sherwood regs, I must admit they seem to have a good reputation for dependability. Well, I did see one "octopus" second stage get hung on the boat gunnel as my friend did a back roll entry. The orange plastic second stage landed on the boat deck, and the metal parts of the demand valve pulled out of the second stage and went on a nice long dive with its owner. I remember the confused look on his face when I showed him the end of his octo hose at 80', terminated by the exposed demand lever. Still not leaking air.
No real problem... could have happened to most any plastic second suffering from that abuse.
It has probably been over 20 years (and more than a few shot glasses of measuring stuff other than air) since I worked on one of those, so I may be missing something or be inaccurate in my description.... so, as usual I invite any enlightenment on the subject.