Question Can the purge button on a G260 be locked?

[rhwestfall]

The D-series dive/pre-dive switch takes the load off the sealing surface, no?

 

[Jacobyz]

Absolutely!
It's been around forever, but Scubapro has dumbed down their best regs.
Sherwood did it with a pin:
View attachment 716228
The old Pilot and 109 did it with the famous "key"
View attachment 716227
This is how I do it with my G250
View attachment 716226
Atomic Aquatics does it automatically with a little spring behind the orifice that pushes the knife edge away when unpressurized. But they just get haters that don't like the open valve during rinsing. But you can't argue with a seat that lasts three years!

Is it on the S620Ti? Nope.
A700? Nope.
New S270? Nope.
Stupid.

Actually, that's not right. It's just their continued support for the dealer model to get you in early for premature service (and to buy a new mask/wetsuit/sparkly thing).

Hey, Rob,

Did you fabricate the seat saver device you use for your 250’s? That solution would be perfect for the 250v’s my grandkids enjoy; with the hand-painted covers matching their custom motifs (including the @James79 custom colored spec boots and saddles for their MK10’s).

Best

 

[rhwestfall]

For sure. it is much better to keep a bunch of OEM and aftermarket seats on hand to avoid buying service kits when the seat and a few orings is all that is needed.

Think about what you just typed... that is all a second stage service kit is...

it is insane that cost of such a kit, or even the price of the OEM seat alone (if you can obtain them).

 

[Pearlman]

Relieves spring tension

The D-series dive/pre-dive switch takes the load off the sealing surface, no?

AFAIK the Venturi switch just channels air in a way (via an internal vent) that when it’s off the airflow provides more resistance on the diaphragm in the opposite direction of when breathing in and this prevents an easy free flow. When the Venturi is in Dive mode the airflow is channelled to the divers mouth in such a way that it creates a bit of vaccum/suction (Bernoulli?) that aids the diaphragm to move in with the breathing making it easier to suck in air…

I don’t think this releases tension on the spring or seat during storage in any way… Venturi only works during active breathing effort.

 

[rhwestfall]

Relieves spring tension

AFAIK the Venturi switch just channels air in a way (via an internal vent) that when it’s off the airflow provides more resistance on the diaphragm in the opposite direction of when breathing in and this prevents an easy free flow. When the Venturi is in Dive mode the airflow is channelled to the divers mouth in such a way that it creates a bit of vaccum/suction that aids the diaphragm to move in with the breathing making it easier to suck in air…

I don’t think this releases tension on the spring or seat in any way… Venturi only works during active breathing effort.

Do you know what a D-series (not the new D420) second stage stage is?

 

[Pearlman]

Do you know what a D-series (not the new D420) second stage stage is?

Nope, but I know that a Venturi effect needs an airflow not seen in a 2nd stage in storage…

 

[halocline]

Thanks, @rsingler. I got it to work. The trick is to only depress the purge button halfway, and then turn it. When depressed all the way, I can't get the button to turn.

It has to be a little difficult to engage or else you might accidentally engage it while diving. This would result in a pretty dramatic free flow.

For me, my personal opinion, nothing more, is that I would rather use 2nd stages where there is no possibility at all of the purge button locking in place. My seats last for years anyways, because I store them with the adjustment knob all the way out and I set them very lightly. Also, if I rebuild a 2nd stage and then know that I'm going to store it for a long time, it's very easy for me to simply give the orifice a 1/4 quarter turn counter clockwise. I just have to remember to set it back before using it.

 

[Open Ocean Diver]

Hey, Rob,

Did you fabricate the seat saver device you use for your 250’s? That solution would be perfect for the 250v’s my grandkids enjoy; with the hand-painted covers matching their custom motifs (including the @James79 custom colored spec boots and saddles for their MK10’s).

Best

The 250V has a seat saver purge button lock, the same as the G260.

 

[halocline]

The D-series dive/pre-dive switch takes the load off the sealing surface, no?

Unfortunately it doesn't, all it does is prevent the lever from fully moving (in pre-dive) to prevent free flows.

AFAIK the Venturi switch just channels air in a way (via an internal vent) that when it’s off the airflow provides

The D series predive switch has nothing to do with venturi effect. There is an internal adjustment for venturi in the D series regs, but that's a completely different part. You might want to have a look at a schematic for this particular 2nd stage design before commenting about it.

The D series seats tend to last a very long time in storage because the spring pressure is very light, and the orifice is relatively big, which means that the spring pressure is distributed over a larger surface area. I routinely have well-adjusted D300s sit for years and then work perfectly.

 

[rhwestfall]

Thanks @halocline

It is a reg I have a few of, but never have the time to really explore them...