S600 Pneumatic Balance Chamber Problem

[oceancurrent]

I have a problem with my S600. After I adjust the orifice (lever height) and the pneumatic balance chamber (spring tension), the regulator breaths fantastic. However only after a dive or two it starts breathing really hard. I have traced the problem to the balance chamber. It looks like it is made to be adjusted fairly easily and when you turn the external adjustment knob, it also tends to tighten the balance chamber screw which it's not supposed to do. Now, I have the A-version of S600, which requires the external balance chamber adjustment tool, which I use. I suspect that the problem has been resolved with the B-version. The question is - is there anything I can do to fix the issue without upgrading the reg to B-version?

 

[redacted]

I can't really offer any help other than I'm pretty sure the A version is the newer configuration and the B version is the older one. Both my G500 and my S600, which I bought when they first came out are B version configuration.

Are you actually able to see where the adjustment has change with use in yours?

 

[oceancurrent]

You are correct, awap. Mine is actually the B version - the one which requires a special tool for adjusting the balance chamber. The newer A version can be adjusted with a screwdriver. And yes, I see the balance chamber adjustment inside going deeper after a few uses with operation of the external adjustment knob. Looks like the balance chamber does not stay put with the rotation of the external knob. Perhaps bad design? Does the A version fix this issue? Is there any way to fix it in the B version?

 

[redacted]

So we do have the same version. I have never experienced the problem you describe. But I developed my own procedure for assembling and tuning these regs befor I got my hands on the Scubapro procedures. I was a bit unsure on how far to screw the balance chamber into the balance chamber piston and decided it made sense to start out with the balance chamber screwed in just far enough that the balance chamber screw slot would be exposed above the balance chamber piston so about 1/32 inch or less I then complete assembly and tune initially with the orifice to just stop any flow. (I don't have any pneumatic tools so it is ma bit of a time consuming process with the last orifice adjustment a 30 degree clockwise turn to stop the leaking.) I then go to the adjustment knob end and turn the balance chamber counterclockwise until it again leaks and then clockwise again in 30 degree inclements turns until the leak stops. The end result is that the balance chamber adjustment hardly protrudes at all into the "seat saver" chamber.

It sounds to me like you may have too little friction between the balance chamber threads and the balance chamber piston threads and maybe too much friction between the adjustment knob threads and the and balance chamber piston threads that the balance chamber is turning on the balance chamber piston threads when you operate the knob. If you remove the knob plug, you may be able to see this happening. Perhaps a little non-hardening loctite on those threads would provide at least a temporary solution

 

[kgault]

I have a problem with my S600. After I adjust the orifice (lever height) and the pneumatic balance chamber (spring tension), the regulator breaths fantastic. However only after a dive or two it starts breathing really hard. I have traced the problem to the balance chamber. It looks like it is made to be adjusted fairly easily and when you turn the external adjustment knob, it also tends to tighten the balance chamber screw which it's not supposed to do. Now, I have the A-version of S600, which requires the external balance chamber adjustment tool, which I use. I suspect that the problem has been resolved with the B-version. The question is - is there anything I can do to fix the issue without upgrading the reg to B-version?

The small O-ring on the stem (A-version) is not to be lubricated, as it not only seals but keeps the adjustment from changing when the knob is rotated. Clean the O-ring well (or replace) and reassemble with clean hands.

Keith