2nd stage does not purge when down to 50 bar

[WhiteSands]

I just did a cleaning of my buddy's 2nd stage recently because the adjustment knob became stuck.

On a recent dive on doubles, we could not unscrew the DIN 1st stage on the left tank. We checked that the valve was closed and purged the 2nd stage attached to that tank. Still no luck.

After some fiddling another dive buddy checked that SPG and it was reading 50bar, although the valves were already closed and regs purged.

I took the 2nd stage and breathed from it and realized I can still breath from it. After depressurizing the line by breathing it down, we could then unscrew the DIN 1st stage.

Is there a problem with the 2nd stage that prevents it from purging all the air out, despite me pressing the purge button all the way down? Nothing came out when I purged, but I could still breath from it. How do I rectify it?

Thanks.

 

[redacted]

I just did a cleaning of my buddy's 2nd stage recently because the adjustment knob became stuck.

On a recent dive on doubles, we could not unscrew the DIN 1st stage on the left tank. We checked that the valve was closed and purged the 2nd stage attached to that tank. Still no luck.

After some fiddling another dive buddy checked that SPG and it was reading 50bar, although the valves were already closed and regs purged.

I took the 2nd stage and breathed from it and realized I can still breath from it. After depressurizing the line by breathing it down, we could then unscrew the DIN 1st stage.

Is there a problem with the 2nd stage that prevents it from purging all the air out, despite me pressing the purge button all the way down? Nothing came out when I purged, but I could still breath from it. How do I rectify it?


Thanks.

Nothing seriously wrong. Some SPGs have such small flow openings that they are slow purging. It may take two or even three purges to allow enough pressure to bleed off.

 

[Couv]

I think The Master's caffeine low level light is on bright.

If I'm calculating correctly, 50 Bar is over 700 psi which is much more than any residual pressure normally left in the system after a purge. It sounds to me like the second stage orifice is adjusted in too far and/or the lever height is too low.

If you gave the regulator a "good cleaning" and made any adjustment changes, it may be best to start from scratch. Often the soft seat get engraved or damaged during an adjustment. To stop freeflow sometimes the orifice is adjusted in too far and cause the problem you've described.

My vote is to replace the soft seat and readjust (remember to hold down the purge button when adjusting the orifice.)

Please let us know what make/model you're working on and the results.

Cheers,

Couv

 

[Diver0001]

I just did a cleaning of my buddy's 2nd stage recently because the adjustment knob became stuck.

On a recent dive on doubles, we could not unscrew the DIN 1st stage on the left tank. We checked that the valve was closed and purged the 2nd stage attached to that tank. Still no luck.

After some fiddling another dive buddy checked that SPG and it was reading 50bar, although the valves were already closed and regs purged.

I took the 2nd stage and breathed from it and realized I can still breath from it. After depressurizing the line by breathing it down, we could then unscrew the DIN 1st stage.

Is there a problem with the 2nd stage that prevents it from purging all the air out, despite me pressing the purge button all the way down? Nothing came out when I purged, but I could still breath from it. How do I rectify it?

Thanks.

The 2nd stage is detuned too much. If you take off the reg-hose there is a little screw inside with slots on adjacent sides of the thread. If you unscrew that by 1/4 a turn then either it will free flow, or the purge will work the way you wanted. You'll see this effect in my experience, most often with Apeks regs.

That said, I have limited experience so... yeah.

R..

 

[Hickdive]

The 2nd stage is detuned too much. If you take off the reg-hose there is a little screw inside with slots on adjacent sides of the thread. If you unscrew that by 1/4 a turn then either it will free flow, or the purge will work the way you wanted. You'll see this effect in my experience, most often with Apeks regs.

That said, I have limited experience so... yeah.

R..

^^^What he said.

Take the second stage off the hose and look inside where the hose connects. You'll see a little fitting with a hole in it and either slots either side or the hole will be a hex.

You can use a screw driver or a hex key to screw that fitting in or out to tune the regulator. Screw it too far out and the diaphragm lever will drop out of reach of the purge button and you'll not be able to purge the regulator as you describe. Screw it in too far and the reg will simply free flow.

It can be a bit of a pain to adjust, put on the hose, pressurise, realise you have to adjust some more, so de-pressurise, remove from hose and repeat until you've got it just right.

If you end up doing it a lot then an inline adjuster like this can be a real help;

 

[Couv]

... Screw it too far out and the diaphragm lever will drop out of reach of the purge button and you'll not be able to purge the regulator as you describe. Screw it in too far and the reg will simply free flow.....

You've got it backwards Brother. But yes, that is the orifice adjustment I'm talking about. However, before we get too carried away it would be best to find out what sort of second stage the OP has. It may be a dual adjustment (lever and orifice.)

 

[Hickdive]

You've got it backwards Brother. But yes, that is the orifice adjustment I'm talking about. However, before we get too carried away it would be best to find out what sort of second stage the OP has. It may be a dual adjustment (lever and orifice.)

It depends on what way you think is in and what way you think is out.

However, before you get carried away you might want to think about what happens to the lever when you adjust the orifice.

 

[j2s]

'Fiddling' w/reg's is not a good idea........Take it to a 'reputable' tech (if you can find one !!! ).....Other wise, use an 'in-line' adjustment tool w/an IP gauge (not by itself ), a Meg gauge ( for 'cracking' pressure ) and an IP gauge attached to the BC hose ( for the 1st stage )......Hook them all up at once, get the 'specs' for your brand and you'll find the problem and/or adjust every thing properly......The tools will pay for themselves after about two rebuilds....'Fiddling" will cause you problems and worse......And don't tell people you have the tools !!!!....Divers will be coming out of the woodwork !!!!!

 

[WhiteSands]

You've got it backwards Brother. But yes, that is the orifice adjustment I'm talking about. However, before we get too carried away it would be best to find out what sort of second stage the OP has. It may be a dual adjustment (lever and orifice.)

It's a HOG Classic 2nd stage.

Classic Second Stage

http://www.scubaboard.com/forums/attachment.php?attachmentid=163449&stc=1&d=1376634637

So can I confirm if I need to screw the adjustment screw clockwise or anti-clockwise?

 

[undrwater]

It's an Allen key for the Hog, but same concept.