Strange IP behavior on a freshly serviced regulator - what's going on?

[caruso]

You don't have to lessen the impact by holding down the purge valve. I'm still gonna!

I'm not understanding the whole "hold the purge button while pressurizing" thing.

First of all it's definitely not common practice, it's not regularly taught, I doubt most divers do it, let alone have ever heard of it (I never did), and you don't see regulators failing at an alarming rate.

Secondly, if everyone did that there'd be annoying hissing all over the dive boat every time someone pressurizes their rig, at least twice for each dive. Picture a cattleboat with 40 hissing regulators.

Thirdly, (and this is just my thinking on this), if you hold the purge button down to avoid the sudden increase in pressure on the regulator, as soon as you let go of the purge button it would appear you will be suddenly increasing the pressure to the regulator- no different than turning on the valve without pressing the purge button. Maybe even worse because the valve can be turned on gradually (which is what I do for the first couple of turns). The purge button is all or none.

Other than opinions about this being a good idea, are there any articles or tech bulletins or anything about it?

 

[Scuba-74]

Secondly, if everyone did that there'd be annoying hissing all over the dive boat every time someone pressurizes their rig, at least twice for each dive.

I just realized that if you do it for your second dive, when your reg is wet, you would be pushing water (often SALT water) into your 1st stage through the hose. That's why, when you rinse/soak the regs, they say never push the purge unless you have an option of putting a reg on the tank, and only then purging it.

I can see maybe holding an inflator button as someone suggested, but I pretty much know I won't risk it with the purge...

I'm still curious if what my reg does is "normal". Certainly didn't seem so for the shop tech (not the one who did the service). It sounds like there can be some explainable difference between "steady IP" and IP just after pressurizing, but not 35 psi difference. I've measured IP many times before on different regs, plus watched quite a few videos where this is done (Alec Pierce for example), and have never seen this behavior.

 

[caruso]

I just realized that if you do it for your second dive, when your reg is wet, you would be pushing water (often SALT water) into your 1st stage through the hose.

Well no, although I question the practice of pressing the purge prior to pressurizing, if it's done just before the rig is pressurized, and the second stage is not submerged, then the chance of any water making it's way up the hose to the first stage is pretty much nonexistent. If you were to watch the Alec Peirce video on this topic you'd realize that even if you submerge an unpressurized second stage in the rinse bin and press the purge button you're still highly unlikely to get any water in the first stage. Note for the casual reader we are not talking about leaving the dust cover off the first stage and dropping it into the rinse bin which would require immediate service.

 

[Rusty Shackleford]

You are going to immediately pressurize it. Any drops of water that attempt to infiltrate will be immediately blown out with a vengeance.

 

[Scuba-74]

If you were to watch the Alec Peirce video on this topic you'd realize that even if you submerge an unpressurized second stage in the rinse bin and press the purge button you're still highly unlikely to get any water in the first stage.

Just did, and I guess you are right. Chances are slim to none.

 

[The Chairman]

First of all it's definitely not common practice, it's not regularly taught,

Neither is neutral buoyancy. I was taught this in my OW class and I teach it in all of mine. If you don't think it's valuable, then don't do it. That won't stop me from babying my regs.

 

[caruso]

Neither is neutral buoyancy. I was taught this in my OW class and I teach it in all of mine. If you don't think it's valuable, then don't do it. That won't stop me from babying my regs.

I'm just looking for information that supports the claim that purging the regulator prior to pressurizing is a useful procedure, when logic and common sense seem to indicate it doesn't accomplish anything more than opening the valve slowly might do. Not saying I'm right but I'm here to learn. I don't blindly accept a technique as valid just because someone thinks it is. If a procedure is not part of a basic open water course, maybe it's because it's not considered beneficial. Conversely there are certainly useful things that are not taught, but that doesn't mean that everything that is left out of an open water scuba course is necessarily useful (such as neutral buoyancy-which I thought WAS part of most basic scuba courses).

Sort of reminds me of divers who use the compressed air from their tanks to dry their dust covers.

 

[Scuba-74]

Sort of reminds me of divers who use the compressed air from their tanks to dry their dust covers.

Is there anything fundamentally wrong with that practice, besides just being annoying? If so, that would be the 3d revelation in this thread for me, and it's only 4 page long.

 

[caruso]

Is there anything fundamentally wrong with that practice, besides just being annoying?.

It accomplishes nothing, it's annoying to other divers, it can be a distraction and detraction from the relaxing scuba experience, and can possibly damage the first stage by forcing air into it. Compressed air released from a scuba tank can cause dirt, debris, bugs, and of course saltwater to fly around a dive boat including into the eyes of other divers.

The practice of blowing compressed air on the dust cover is covered by Alec Peirce Scuba in the following video at 6 minutes 30 seconds.

 

[Scuba-74]

It accomplishes nothing, it's annoying to other divers, it can be a distraction and detraction from the relaxing scuba experience, and can possibly damage the first stage by forcing air into it. Compressed air released from a scuba tank can cause dirt, debris, bugs, and of course saltwater to fly around a dive boat including into the eyes of other divers.

The practice of blowing compressed air on the dust cover is covered by Alec Peirce Scuba in the following video at 6 minutes 30 seconds.

Well, he doesn't say don't do it He says there are other ways of doing it, which is a slightly different thing. He also says pay attention to others if you are doing it, which is common sense.

I often choose to do it by blowing on the cap or using a towel in conditions that would make compressed air blowing less desirable. But in my opinion, compressed air is faster/easier, and if I don't have anyone right next to me, and I'm not at a serene shore location where it can disturb others, I don't see harm in doing it in short bursts of air at under 500 psi.