What are the symptoms of a too-short pin in RAM?

[halocline]

Put all the 1st stage internals in the other regulator you got the balance chamber from. If it doesn't creep it's the volcano orfice.

That's a good idea. Regarding the main spring, a weak spring will cause IP to drop, not creep up. IP is the force required to overcome the spring pressure, so if that spring doesn't hold steady force on the diaphragm, the reg can lock up at a lower IP with each breath. That was a symptom in a DA I had until I replaced the spring with one of the ones Herman found.

There are only two places HP air can "leak" into the IP chamber causing IP creep. As I'm sure you know, those are the orifice and the balance chamber, and if you've tried a couple of balance chambers and you're certain the small o-ring is sitting in the right spot, my money would be on the orifice.

I would not be afraid to use the right kind of abrasive on it. I use micromesh, which goes to 12000 grit and is a very even, refined grit pattern. I wrap it around a pencil (eraser end!) and polish away. I think Bryan uses jeweler's rouge or something like that.

 

[Double Diver]

That's a good idea. Regarding the main spring, a weak spring will cause IP to drop, not creep up. IP is the force required to overcome the spring pressure, so if that spring doesn't hold steady force on the diaphragm, the reg can lock up at a lower IP with each breath. That was a symptom in a DA I had until I replaced the spring with one of the ones Herman found.

There are only two places HP air can "leak" into the IP chamber causing IP creep. As I'm sure you know, those are the orifice and the balance chamber, and if you've tried a couple of balance chambers and you're certain the small o-ring is sitting in the right spot, my money would be on the orifice.

I would not be afraid to use the right kind of abrasive on it. I use micromesh, which goes to 12000 grit and is a very even, refined grit pattern. I wrap it around a pencil (eraser end!) and polish away. I think Bryan uses jeweler's rouge or something like that.

I agree with The Captain and Mattboy. If you swap the HP seat and spring block to the Conshelf and it holds, the only thing left is the orifice. So your choices are limited, ether polish or pay, you can always get a new used body from VDH. Now you sound like a reasonable fellow who is mechanically inclined, so take your time, go easy and clean and reassemble often. You don't want to remove more material that needed. Good luck!

a

 

[duckbill]

I've never had a problem with a 2-stage "honking", but one of my Mistrals had that problem after a rebuild, and I tried everything to stop it. It only stopped after I replaced my new, supple diaphragm with one that was a little stiffer. That took care of the resonance problem in that case. If you installed a silicone diaphragm, try using your old one and see if the problem goes away.

 

[Nemrod]

That's a good idea. Regarding the main spring, a weak spring will cause IP to drop, not creep up. IP is the force required to overcome the spring pressure, so if that spring doesn't hold steady force on the diaphragm, the reg can lock up at a lower IP with each breath. That was a symptom in a DA I had until I replaced the spring with one of the ones Herman found.

There are only two places HP air can "leak" into the IP chamber causing IP creep. As I'm sure you know, those are the orifice and the balance chamber, and if you've tried a couple of balance chambers and you're certain the small o-ring is sitting in the right spot, my money would be on the orifice.

I would not be afraid to use the right kind of abrasive on it. I use micromesh, which goes to 12000 grit and is a very even, refined grit pattern. I wrap it around a pencil (eraser end!) and polish away. I think Bryan uses jeweler's rouge or something like that.

The regs I have had with a weak spring on the diaphragm would not set to a proper IP, only able to get it to around 110 psi or less, continued cranking of the internal hex nut resulted in the spring coils touching, solid column, and then erratic, and then rising IP. At least that is what I recall, could be I don't remember right.

N

 

[FlyernDiver]

Busy day so things are still as they were yesterday.

Thanks for all of the excellent suggestions. I will put the balance chamber back in the Conshelf as soon as I get a few spare moments--such an elegant troubleshooting technique! Now why didn't I think to do that?

To elaborate on the honking sound, it isn't like the honking one would get out of a poorly tuned single hose, I can only describe it as "something ain't right" almost tinny sounding with less consistent pitch than a single hose. I suppose the honking could be related to the IP creep as it usually happens at the start of the inhalation cycle and again only at high tank pressures.
I do have a spare pin though, so I will cut that one a schosch longer and with a square end (not pointed) this time. If I understand the pin's function correctly it can affect flow volume and given that I think it's just a bit shorter than spec, it could be a contributing factor.

As an aside, I sure am glad you guys beat me into getting that band clamp! It's not as stout as I would like, but it does the job nicely. If I were screwing with c-clips all this time, I would certainly have jettisoned this reg long ago.

Thanks again, I will report back as soon as I get a chance to work on it more--hopefully tomorrow.

 

[FlyernDiver]

...and I will try the old rubber diaphragm that is still in good shape if the honking persists...

 

[Gilldiver]

I had similar problems with a RAM, what it came down to were scratched/groves in the spring block.

Also as it is occurring at high psi, do you have the backing ring in the spring block behind the O-ring? I put in a new Conshelf block with new o-ring and backing ring and it locked solid.

 

[Nemrod]

That honking sound, sometimes I think it is related to the push button adhering to the rubber diaphragm. I polish the button smooth and then lubricate the interface with either a dab of silicone grease or appropriate grease for the breathing mixture. N

 

[captain]

Most of the honking occurs above the surface because the water acts as a dampener to diaphragm. One thing I have found is DA's DAAM's and RAM's are sensitive to diaphragm position in relation to the horseshoe, DA's more so than the latter.

If contact points on the diaphragm tabs and horseshoe contact surface aren't as close to equal as possible it causes or increases the chance for honking. I have been able to eliminate honking by careful positioning of the diaphragm.
I find centering the contact point on one side may cause it to be off center on the other side. It is a split the difference situation when positioning the diaphragm. The diaphragm tab contact point may not be centered on either either side but will be equally off center on both sides.

 

[FlyernDiver]

After swapping parts around a bunch of times, I am confident that the problem is in fact a nicked orifice. Everything I have works beautifully in my Conshelf. I think I can see a very small radial scratch in the sealing face.

If it isn't one thing, it's another...