second stage - pressurize/depressurize

[hedonist222]

How does it breathe when you suck in hard?
How does it breathe with a gentle small inspiration?

Breathes completely normal.

 

[hedonist222]

I guess that the behavior observed by the OP is due to the small orifice in the HP hose to the SPG.
If the HP hose has a very small orifice, it will inflate the HP hose internal volume and the SPG slowly. Furthermore if you close the tank and purge the second stage, it will also take some time to release the pressure inside the HP hose and SPG.
I've seen this in a brand of HP hoses where the orifice is so small that it takes time to presurize the system. This is, however desirable at some point, as it will preserve better the life of the spg and second stages, and in the case of a catastrophic failure of the HP hose, the tank will empty also slowly.
Some other HP hose brands this orifice is not so small, so, the pressure in the system rises more violently.
View attachment 649802
I've also seen HP hoses where the orifice was so corroded that it hardly passed any air to the SPG.

I get your point but I've used this same spg with the scubapro setup and it wasn't like this.
Instantly de-pressurized.

EDIT
Because I cannot remember with confidence how it de-pressurized. I will pause the above comment till I can attach a new scubapro SPG and test de-pressurizing.

 

[hedonist222]

So, more questions, do you have an SPG on the scubapro? How does the APEKS breath and same for the SP? What first stage on the SP?

as pointed out if there is a HP (SPG) hose on one and not the other this could easily be the slow bleed back from that hose = normal. If you do have an HP hose on both it may the more rapid flow of the bleed inherent in the first stage design or it maybe a designed limit to the purge of the APEKS second stage, I’m not hands on familiar with the XL.

No spg in the scubapro.
The apeks appears to breathe fine.
The s 620 ti is connected to a mk 25 Evo.

 

[lexvil]

I get your point but I've used this same spg with the scubapro setup and it wasn't like this.
Instantly de-pressurized.

Then when under pressure with it set for a dive, minimum adjustment and dive/pre-dive set to dive can you make it freeflow by pushing the purge?

 

[lexvil]

No spg in the scubapro.
The apeks appears to breathe fine.
The s 620 ti is connected to a mk 25 Evo.

I think you have the main answer then, no hp hose to bleed back.

 

[hedonist222]

So I reversed my setup.

In this video, I connect the gauge to my Scubapro setup (MK 25 EVO + S 620 Ti):

I noted that de-pressurizing took about fifteen seconds. With the Apeks, it also took about fifteen to sixteen seconds.


I then checked how long the Apeks would de-pressurize without a gauge (or a faulty gauge?):

Again, it took significantly less time but not as swift as the ScubaPro.

 

[hedonist222]

So, more questions, do you have an SPG on the scubapro? How does the APEKS breath and same for the SP? What first stage on the SP?

as pointed out if there is a HP (SPG) hose on one and not the other this could easily be the slow bleed back from that hose = normal. If you do have an HP hose on both it may the more rapid flow of the bleed inherent in the first stage design or it maybe a designed limit to the purge of the APEKS second stage, I’m not hands on familiar with the XL.

During the first set of videos, no, no SPG on the scubapro system.
Apeks breathes fine with/without an SPG.

 

[lexvil]

Those tiny orifices in HP hoses do take a long time to bleed. Between a diaphragm and piston the piston opens up bigger and faster, nice Regs, just picked up a 620 to try out, I’ve always liked the 600 and this does appear to be a bit nicer.

 

[hedonist222]

lexvil, thank you. The S 620 Ti is maginificent. Effortless breathing even when upside down.

I still want to try a brand new SPG to confirm that it is truly the smaller SPG orifice that is impeding on the de-pressurizing.

 

[lexvil]

lexvil, thank you. The S 620 Ti is maginificent. Effortless breathing even when upside down.

I still want to try a brand new SPG to confirm that it is truly the smaller SPG orifice that is impeding on the de-pressurizing.

The bast way to test the bleed speed of both is no SPG, just plug the port.