Joining the 109 Club

[rhwestfall]

Oops... When you have parts left over....:nono:

 

[James Sizemore]

Also, a AA Battery works great for pushing that o-ring in place.

 

[James Sizemore]

I have an IP of 125psi spot on at 3000psi, 100psi at 500psi. The 100psi seems low. or should I cycle it a few times to let parts fully seat?

 

[rhwestfall]

That is low. Were there any shims in it when you tore it down?

 

[James Sizemore]

I had one shim placed on top of the spring.

 

[Couv]

Bryan had shims manufactured in two different thicknesses which simplify the job of adjusting the IP to where you want it. (125-135 psi at low or high tank pressure)

ScubaPro piston spring shims now available from VDH

 

[Nemrod]

I love the 109, and have serviced and use several of them, both balanced and unbalanced, but have yet to have any of them on a ScubaPro 1st. Is this a faux pas?


Bob

I use the Tekna/Oceanic clones of the MkV. I put a SP HD yoke on my best one.

IMO, I would set for an IP of 135 PSI, you need to shim the spring up it sounds like.

N

 

[James Sizemore]

Just ordered shims from VDH. Now more waiting.

 

[halocline]

I have an IP of 125psi spot on at 3000psi, 100psi at 500psi. The 100psi seems low. or should I cycle it a few times to let parts fully seat?

100 is really low, but the big problem is 25 PSI difference in IP between 3K and 500 tank pressure. Something is wrong; either your HP o-ring isn't seated properly and is extruding excessively, or there's not enough lubricant between that o-ring and the the piston, or the HP o-ring is too soft. There might be a connection here with the fact that you did not use a bullet....a big mistake. You might have damaged the HP o-ring enough so that it doesn't leak right now, but is causing lots of friction. These are all educated guesses.

I would cycle it 50 times or so by tapping on the purge and leave it pressurized for several hours, then see if the IP difference between full and empty tank diminishes. Maybe there is enough slop between the seat and piston to allow air through when the pressure gradiant is high enough. If that's the case, breaking in the seat should lower the IP at high pressure to about 110 or so. Then you could add shims.

But I would be pretty suspicious that something's not right with the HP o-ring. The best ones I've used are 90 duro polyurethane. Their shelf life is not great, though, so you have find them fresh. EPDM or viton 90s work okay too. And get a bullet, they cost about as much as an air fill.
http://www.scubatools.com/p-470-scubapro-piston-bullet-brass.aspx

 

[Bryan@Vintage Double Hose]

I printed the shipping label for you shims but no mail service today due to the holiday. I also included a couple of piston O-rings and a bullet tool. Working with shims without the bullet is an exercise in futility.
Below is a link to hard and soft seating by Pete Wolfinger. Great information to become familiar with no matter what regulator you are working with. Dropbox - High and low pressure seating.pdf