Scubapro 109 Seat Savers

[rhwestfall]

A minor skirmish at best - but you have to wait for the guys on the other coast to wake up.

 

[redacted]

So does that mean that seat savers are needed/recommended or not? Or will this question set off a holy war...

Tough question. Clearly, LP seats will experience some engraving in storage as the full pressure of the mechanical spring presses the soft seat into the orifice and that groove will change flow characteristics a bit. I'm not sure if it really matters. I suspect that if you service per the mfgr recommendations, it will not matter. But I also see a number of design efforts by manufacturers to reduce this effect. We still see current 2nds sporting a "seat saver" feature. I'm not sure whether it matters or is just another sales gimmick.

With 109s, there are a few options for seat savers. Either of the 2 SP produced designs (I prefer the key) or some improvised device. I even went for a while just leaving off the retaining clip and backing off on the knob a bit more in storage. I don't bother doing anything special with my D-series and coaxial valve Pilot as the spring force is pretty light to begin with and the seats seem to be fairly substantial. I do store my 156s with the purge depressed but that, along with the newer SP balanced 2nds does have a lighter string so less critical. And, now that we realizes there are compatible after-market seat, the problem (and expense) of getting new seats is greatly reduced. With the classic downstream design of most of the unbalanced 2nds and my 109s (and a few plastic 2nds that are unbalanced barrel poppets) I'm still going with the seat saver. I got started doing that with my Air2s that occasionally seemed to require a little adjustment after storage to stop a small freeflow. They are hard enough to get good performance and stability from anyway and I saw no sense in compromising what I could get. With the adjustment knob on a 109, it is likely unnecessary, but I just have not found the down side. I have seen some slight deformity in some covers (I don't recall which style). I have seen enough deformity that it would cause a slight freeflow if immediately put under pressure. But the deformity seemed to be only temporary and the freeflow problem would disappear rather quickly (minutes) after removing the device. I also store my R-series regs with the purge depressed. Some older R190 have a built in device and a bottle cap and bungee works well on newer ones. I also have an R380 (or one of the other small ones) that seems to be a bit marginal on performance/stability that I use on a pony. I had a dive/predive switch that was nothing but a purge depressor but didn't work worth a damn. I switched out the cover with one from an S550 which has the metal "S" that accepts the 109 purge depressor key.

So, my answer is that I believe it does help with some of the low end designs, is unnecessary with some of the high performance designs, and does not seem to hurt with any. YMMV

 

[captain]

I have a 30 year old 109 with the original seat, still works like new, always stored with the seat save and the adjuster backed all the way out.

 

[Zung]

So does that mean that seat savers are needed/recommended or not? Or will this question set off a holy war...

This is a relatively tame topic. If you want blood, start another thread on AIR2 vs octo.

Another way of looking at this:

• Do you have your reg serviced every year or every other year?
• If you service your reg yourself, can you buy kits or parts easily?

If the answer is yes to any of the above, don't bother wth the seat saver.

 

[BenjaminF]

This is a relatively tame topic. If you want blood, start another thread on AIR2 vs octo.

Another way of looking at this:

• Do you have your reg serviced every year or every other year?
• If you service your reg yourself, can you buy kits or parts easily?

If the answer is yes to any of the above, don't bother wth the seat saver.

I was a bit worried about that. I'm not against feeding the trolls sometimes, but this is something that I would like to learn more about.

I'm hoping to start servicing my BAs, but I still have to lay my grubby hands on the tools. Until then I need to either not service them for two or so years, or convince the SP repair guy in this area that I DO want him to service them and not to try and sell me a newer set.

Given that, should I try to get hold of some sort of seat saver, or is the time-span sufficiently short that I should live through it?

 

[Zung]

Either way is fine, flip a coin: you'll live.

But you don't need 2 years to gear up. Assuming you have a MK5 or a MK10 1st stage, the only special tools you need are a bullet tool and an IP gauge. The rest is just normal hand tools.

 

[BenjaminF]

Busy searching for one of those now online. Until then, I have a mk25 that was sitting unused elsewhere.

 

[Zung]

The MK25 is even better: no special tool required, just the IP gauge, any LDS should have it.