Circuit under pressure with tank closed after purging

[npole]

Does anyone had a similar issue or can explain how this would affect the LP ports?
Story: apparently there's pressure "trapped" in the circuit even after have removed the first stage from the tank, this someway "locks" the HP ports and the SPG doesn't work (it remains to zero) if not after purging/dismounting the first stage a couple of times.
Does anyone has a technical explanation of how the residual pressure in the circuit would affect the spg from not moving at all (ie: shut down both the HP ports).
It's Scupapro Mk11.

 

[halocline]

I'm having trouble understanding your description. Can you try to describe what happens a little more completely?

 

[The Chairman]

Take a bit longer to purge the system... pressure is throughout the reg and takes time to relieve it'self. Sucking on a reg really seems to help that.

 

[tursiops]

Does anyone had a similar issue or can explain how this would affect the LP ports?
Story: apparently there's pressure "trapped" in the circuit even after have removed the first stage from the tank, this someway "locks" the HP ports and the SPG doesn't work (it remains to zero) if not after purging/dismounting the first stage a couple of times.
Does anyone has a technical explanation of how the residual pressure in the circuit would affect the spg from not moving at all (ie: shut down both the HP ports).
It's Scupapro Mk11.

Why do you think there is residual pressure in the regulator once the first stage is removed from the tank valve?

 

[northernone]

• An extra few seconds purging bleeds the lines. Depending on the reg and hoses not all the pressure bleeds out in the initial blast. Think pouring syrup from a bottle. The first 90% pours quick and the last 10% takes days... But much faster in the case of scuba plumbing. It doesn't show on the gauge because it's only a few psi above ambient. Does that make sense?

 

[АлександрД]

I think I understood your question
I`m already wrote about my way to clean regulators, using this trick
Salt Deposits

Two tricks for cleaning your reg:
2. When you try to disconnect 1st stage from tank - after closing valve do not drop the pressure less than 20bar. Then try to disconnect DIN or Yoke carefully from valve. It will make "psssst", and stops. Do not press purge button on 2nd stage after! You should stay pressure in the hoses.
When you make this step - you can loose HP o-ring, be carefully. Put it back to the sink.
Than close hole in the 1st stage by finger, and then put regulator to the fresh water and shake it storngly.
THAN shake it from water drops, remove finger, AND SLOWLY press purge button.
When pressure in the hoses will drop less than IP (setup pressure or Intemediate Pressure), you 1st stage will opening, and air starts to go from hoses, over regulator, over the filter to the out.
It allow you to get some dividents:
Your filter will be cleaned from any possible drops of water.
You filter will be cleaned from any rust particles from the tank.
And you be able to see, how it clean, when you will put you palm before air stream. All particles will stay on your wet palm (I hope you are freshed regulator before )
And also that allow to prevent water ingress inside regulator when you will freshening it.

So - one thing is described in my message. When you disconnect 1st from tank, and NOT purge off pressure - you will have air in the pipes, and 1st stage valve will be closed, until you will start to press 2n stage button.

Another thing I saw with connected regulator.
When you close tank valve, and then press purge button on the 2nd stage, you hear as all air goes out.
You can release button, wait a little, press it again, and listen psst again!!!!
Air storing in HP hose. It has very very small pinhole at the end, and air going from HP hose to the regulator and LP hoses very slowly

 

[npole]

So the info are "reported" from my buddy, I yet have to check it myself.. and it sounded strange to me, once the post.

I say there's air in the circuit because disconnecting (physically) the spg from the first stage, you can literally listen the (residual) gas leaking from the port after have purged it completely.

This could be perfectly normal (I never tried it myself... never I had a reason to try it out), however the opinion of who examined the first stage is that there's an issue with the LP port that is affecting the HP ports. Both the HP ports have the same issue, and the spg is working fine on another first stage (and as opposite another spg isn't working on the affected first stage).

I'm trying to collect info of why it's happening, surely the thing will be serviced now, but I'm curious as I never heard of this issue before and I'm trying to figure what it could be, since the connection of the valve to the HP ports should be pretty "direct".

For an easy explanation of what's happening:

The spg (any spg) often doesn't move from zero or show only few bars, and it fixes by opening/closing/purging the gas in the circuit (some times two or more times). It happens to both the HP ports.

 

[npole]

Air storing in HP hose. It has very very small pinhole at the end, and air going from HP hose to the regulator and LP hoses very slowly

I understand that is someway natural for it to happens... but the question is: why the air trapped in the hose should affect the SPG in the next dives? Even if there's some air trapped in the HP hose, as soon you open the bottle again, the pressure will kicks in, and the spg should work normally... unless the issue is something else.

 

[johndiver999]

There is some elasticity in the hoses,

 

[АлександрД]

It is just SPG problems and roughness.
Knocking by finger on SPG - and arrow can move a little...
Well working equipment SHOULD NOT have correlation between dives!