Conshelf XII?

[Creed]

I recently picked up a Conshelf XII. At least, the decal says XII. The spring retainer is flat compared to the XII's I've seen online. Also, the adjustment screw is hex, and not slotted. The body is the same size as a XIV, with 1 HP and 2 LP ports. Did the XII have a different spring retainer at some point, or is this a XI with a different decal?

 

[DA Aquamaster]

I recently picked up a Conshelf XII. At least, the decal says XII. The spring retainer is flat compared to the XII's I've seen online. Also, the adjustment screw is hex, and not slotted. The body is the same size as a XIV, with 1 HP and 2 LP ports. Did the XII have a different spring retainer at some point, or is this a XI with a different decal?

With the flatter cap and slotted spring pad adjustment screw, it sounds like an XI with a XII yoke screw. The XI I have uses a flat metal yoke screw rather than the plastic knob.

The port arrangement on my Conshelf XI has 2 LP ports and 1 HP port with the ports at 12 o'clock, 4 o'clock and 8'oclock positions. In contrast my Conshelf XII has the same number of ports but has them at 12, 3 and 6 o'clock positions.

 

[Creed]

DA, do you happen to have a repair manual for the XI? I assume that it uses the same parts as the rest of the Conshelf series.

 

[DA Aquamaster]

Our shop does not have a manual that old for USD regs. But when I rebuilt mine, the current Conshelf first stage annual service kit did the job nicely. The o-rings and seat appear identical and work fine even though the balance chamber is a little different. I noticed the newer diaphragms are a little thicker but they are the correct diameter and work fine.

So basically, it comes apart and goes together like a XIV, 21, etc.

 

[Creed]

I just disassembled the rest of the reg. It has some brass showing, but the 2nd at least was in working order. However, the yoke nut is stuck, and with the edges already bunged up a bit, I am afraid of ruining it. Any suggestions?

 

[DA Aquamaster]

I am assuming this is a Mk XII yoke nut with two faces only?

My thoughts would be to soak the reg in hot water initially to try to loosen the deposits that are holding things together.

Plan B would be to soak it in a warm solution of either 3% to 4% HCL (4 oz of muratic acid from the local harware store or Wal-mart garden department and 32 oz water - add the acid to the water, not the water to the acid.) or a vinegar and water solution. The acid will help remove the salt deposits.

It won't harm the chrome as long as it is intact, but will remove the chrome that is already corroded and green looking. I normally use a 5 minute to 15 minute soak depending on how crusty things are.

Over torquing the yoke nut is a common problem that only gets worse with salt deposits and a little corrosion.