Breathe down check pool lesson 2 ???????

[deepbreath]

I have asked this question of several people as to what it means, and had many different replies, to me I think its a check of the exh valve in the 2nd stage, what do you think.

Nick.

[crofty]

I have asked this question of several people as to what it means, and had many different replies, to me I think its a check of the exh valve in the 2nd stage, what do you think.

Nick.

Not sure what it means, but I use as
1. Check the pillar valve is not leaking when closed
2. Give the students a good idea of the feeling when getting out of air.

maybe I am wrong

[John Williams]

:=I have asked this question of several people as to what it means, and had many different replies, to me I think its a check of the exh valve in the 2nd stage, what do you think.
:=
:= Nick.

Not sure what it means, but I use as
1. Check the pillar valve is not leaking when closed
2. Give the students a good idea of the feeling when getting out of air.

maybe I am wrong

All useful checks so far...though the best test of a leaky (when closed) pillar valve is surely less in your cylinder this weekend when you had it filled last weekend!!!

Breathing it down also
1) helps you to see if the pressure guage is "sticky" and might stick underwater - or if the operation is smooth and unlikley to stick on the dive.
2) once the system is breathed down to 0 then you should not be able to breathe in...if you can there is a fault in the 2nd stage:
a) the exhaust valve is unseated or faulty
b) the diaphragm is unseated or faulty

If the first stage (or indeed anything up stream of the second stage) were leaking then the "turn it off and watch the guage for a minute or so" test would show it up.
Don't rely upon this tough...a bubble check just into the dive is sound practice too.

HTH

John

[deepbreath]

:=:=I have asked this question of several people as to what it means, and had many different replies, to me I think its a check of the exh valve in the 2nd stage, what do you think.
:=:=
:=:= Nick.
:=
:=Not sure what it means, but I use as
:=1. Check the pillar valve is not leaking when closed
:=2. Give the students a good idea of the feeling when getting out of air.
:=
:=maybe I am wrong

All useful checks so far...though the best test of a leaky (when closed) pillar valve is surely less in your cylinder this weekend when you had it filled last weekend!!!

Breathing it down also
1) helps you to see if the pressure guage is "sticky" and might stick underwater - or if the operation is smooth and unlikley to stick on the dive.
2) once the system is breathed down to 0 then you should not be able to breathe in...if you can there is a fault in the 2nd stage:
a) the exhaust valve is unseated or faulty
b) the diaphragm is unseated or faulty

If the first stage (or indeed anything up stream of the second stage) were leaking then the "turn it off and watch the guage for a minute or so" test would show it up.
Don't rely upon this tough...a bubble check just into the dive is sound practice too.

HTH

John


Yes all makes sence, thanks gents, never thought about the gauge sticking, good stuff.

Regards nick.

[Tim Bartley]

I have been told that breathing in too forcably when at 0 can invert the diaphragm on the first stage.
Any comments?

[John Williams]

I have been told that breathing in too forcably when at 0 can invert the diaphragm on the first stage.
Any comments?


Yeah!

Don't suck too hard!
(just enough to do the job)

John

[Andy Wade]

:=I have been told that breathing in too forcably when at 0 can invert the diaphragm on the first stage.
:=Any comments?
:=

Yeah!

Don't suck too hard!
(just enough to do the job)


I was going to make a really cheap joke, but nah, too obvious.
I'll get my coat.
;-)

[John Williams]

:=:=I have been told that breathing in too forcably when at 0 can invert the diaphragm on the first stage.
:=:=Any comments?
:=:=
:=
:=Yeah!
:=
:=Don't suck too hard!
:=(just enough to do the job)
:=

I was going to make a really cheap joke, but nah, too obvious.
I'll get my coat.
;-)


Beleive me ...it took REAL restraint not to...where's MY coat!

J

[Philip Smith]

I have been told that breathing in too forcably when at 0 can invert the diaphragm on the first stage.
Any comments?

It's unlikely to damage anything in the first stage. I have heard it said that it may be possible to reverse the exhaust valve in the second stage, but I'm not sure how realistic that is nowadays. I suppose it's also theoretically possible to damage the second stage diaphragm.

Philip Smith

[Mike Halligan]

It's unlikely to damage anything in the first stage. I have heard it said that it may be possible to reverse the exhaust valve in the second stage, but I'm not sure how realistic that is nowadays. I suppose it's also theoretically possible to damage the second stage diaphragm.

Philip,

If, as happened here (well at least it did in the NW) exactly 12 months ago the importer/distributor knocks out sub-standard service kits, then the 2nd stage diaphragm collapses as you first inhale below 3m. Which is very interesting!

Then you get what Keith describes in Travel Club Forum, the 6 stages of customer service.
1. Ignore
2. Procrastinate
3. Fob off
4. Deny
5. Token gesture
6. Sort it out
Fortunately, my technician sorted it and then took things up with the importer himself.

Mike

[David Walker]

Don't rely upon this tough...a bubble check just into the dive is sound practice too.

Hehe - bubble checks with some people can be scary! They have streams of bubbles coming out just about everywhere, you sort of get their attention and point at it, and they just look and give you the OK... I've been diving with people where just about every connection had a little leak, including air coming out of all the teeny holes on the high pressure hose (and at the time I didn't know the high pressure hoses were supposed to leak like that at higher pressures so that was very odd!), drysuit hoses, regs with slow leaks, first stage bubbles, everything! I think i'd rather not look with some people!

David

[clive cobby]

:=I have asked this question of several people as to what it means, and had many different replies, to me I think its a check of the exh valve in the 2nd stage, what do you think.
:
Its to check if the exhaust valve is seated correctly. If you can still get gas with the first stage shut off then the valve needs re seating, dip 2nd stade in water blow hard often re seats valve. If you dive with it leaking you will get air/water mix