Regulator checklist and inspection

[ECpirates96]

Great post thanks. Bump!

 

[Cave Diver]

olice:Gentlemen,

The Rev-7 check list has been split off and made a sticky at the top of the forum with a redirect to this thread for discussion. Just for future reference, if anyone wishes to have a sticky made please use the Report button or PM one of the Mods to review. I just stumbled into this thread for the first time tonight by accident.​

 

[Atticus Lake]

Thanks very much for this awesome resource!

I have a small question on cracking pressure:

Air should begin to flow before the regulator gets more than 1 1/2 inches deep.
If the mouthpiece is submerged before the regulator starts to flow, the cracking
pressure is probably too high.

Do you mean when front of the reg (purge button) is 1 1/2 inches deep? Or the intake hose / adjustment knob? Presumably not the mouthpiece?

Thanks!

 

[redacted]

Thanks very much for this awesome resource!

I have a small question on cracking pressure:



Do you mean when front of the reg (purge button) is 1 1/2 inches deep? Or the intake hose / adjustment knob? Presumably not the mouthpiece?

Thanks!

Actually, the answer is the face of the diaphragm which is just behind the purge button, probably anywhere from 1/16th of an inch to 3/8ths inch depending on the specific model.

 

[knowone]

With the regulator fully assembled, horizontal, square, plumb, with the faceplate down, mouthpiece up, measured from the front of reg, purge button, faceplate.

The reason for so many words is that some regs
have a faceplate incorporated purge, with no button.

awap is correct.

If you want precision use a Magnehelic setup.

 

[Blue Sparkle]

I agree; this is fantastic. When I read it some months ago, I did not own a regulator and it sounded complicated and just didn't make sense. Now that I have one, and have re-read this, I'm looking forward to being able to make these checks (next time I have a tank available).

On the cracking pressure question, couv wrote this up in post #6... maybe it clarifies?

Regulator second stages have a diaphragm inside. During normal use, one side is exposed to water (hydrostatic pressure) and the other side is dry. The diaphragm not only keeps the side you inhale dry, it actually performs the work (through mechanical linkage) of opening the air valve. So the key is how far the diaphragm can submerge (mouthpiece up) before the air valve opens. This is known as the "cracking pressure" and is usually measured in inches of water. Now, it may not be easy to determine exactly when the diaphragm is first exposed to water pressure, so we used the term "regulator". At any rate, when the regulator second stage is submerged, air should begin to flow before the mouthpiece is under water.

Edit: Oops, looks like awap and knowone posted while I was typing; sorry about the redundancy.

 

[knowone]

Redundancy, or understanding regs to avoid it's necessity is good.

 

[Bogie]

Thanks for the great advice.

 

[Zung]

...If you want precision use a Magnehelic setup.

Or go cheap and rig up a manometer for a couple of bucks.

 

[HenrikBP]

Zung, that's an awesome manometer! Now just get a center-finding ruler and you have the perfect portable tool

Henrik