Setting Regulator breathing resistance

[Nitrox_DiverNY]

Hello all, I was watching a video by the master Alec Peirce Scuba on setting the breathing resistance of a reg, and it looks quite easy to do. The reg im using is only a few months old but can benefit from some tweaks in the breathing resistance. Is there any reason why I shouldn't attempt this myself? The reg im using is a HOG D3 that has a breathing resistance knob and Venturi. I figured id get it to the edge of free flow with the breathing resistance knob turn on its easiest setting to breath and Venturi on low, does this sound right? The inline adjustment tool seems like it will come in handy too and I will save some money doing it.

 

[stiebs]

The venturi adjustment will only affect dynamic performance; ie, it will not change the "cracking" effort of the reg. Once air is flowing, the venturi adjustment changes the turbulence properties of the air flow through the reg, making reducing breathing effort during normal inhalation/exhalation cycles.

When tuning a reg, it should be tuned with the adjustment knob wide open, and then adjusted using the inline tool so cracking effort is to manufacturers spec (usually somewhere around 1.2-1.4 inches of water)

It is an easy adjustment to make, and if you have the tools and desire to do it, there's value in doing so, especially as the seat settles shortly after a service. It's best to only make adjustments whilst there is no pressure on the seat (ie, purge pressed in) otherwise the rotating movement of the sharp edge of the orifice can cut into the soft seat surface.

Some of those YouTube videos are great, but if you're interested in the topic, you'll be much better off getting a hold of Regulator Savvy.

 

[Nitrox_DiverNY]

The venturi adjustment will only affect dynamic performance; ie, it will not change the "cracking" effort of the reg. Once air is flowing, the venturi adjustment changes the turbulence properties of the air flow through the reg, making reducing breathing effort during normal inhalation/exhalation cycles.

When tuning a reg, it should be tuned with the adjustment knob wide open, and then adjusted using the inline tool so cracking effort is to manufacturers spec (usually somewhere around 1.2-1.4 inches of water)

It is an easy adjustment to make, and if you have the tools and desire to do it, there's value in doing so, especially as the seat settles shortly after a service. It's best to only make adjustments whilst there is no pressure on the seat (ie, purge pressed in) otherwise the rotating movement of the sharp edge of the orifice can cut into the soft seat surface.

Some of those YouTube videos are great, but if you're interested in the topic, you'll be much better off getting a hold of Regulator Savvy.

thanks for the reply, that was very helpful!! im going to check out Regulator Savvy. Safe Diving!

 

[rsingler]

Keep in mind that adjusting the orifice with the inline tool directly and profoundly affects lever height. Adjustments that technicians make are in 1/12th of a turn increments (5 min on a clock face).
So if you need to add 1/4 turn to eliminate a freeflow, you may now have a reg whose lever is so low it will not deliver sufficient air at 4 atm (99ft/30m).
And conversely, tuning to the edge of freeflow with your orifice so you can add back resistance with the knob may raise your lever so high that it is pressed firmly against the back of the diaphragm. That may make it unstable in use.
Reg tuning isn't rocket science, but there are quite a few hidden pitfalls (like cutting the seat with the orifice that @stiebs noted above).

 

[Jim Lapenta]

You also need to understand that using the in-line tool should only be used as a last resort on a reg with a few dives on it. You may not hit the groove in the LP seat exactly and start to create another one. Where those intersect you run the risk of leakage.
In addition, if this is a newer Classic or the Zenith second stage on the D3 there is a micro adjust that increases spring pressure without the need to adjust the orifice. The D3 refers to 1st stage only.
There is no D3 second stage.
Also, adjusting the orifice so that the reg just barely doesn't hiss is a bad idea because as the seat wears just a little, you'll have to use the adjustment knob more and more and that in effect reduces the life of the seat. There is no need to have cracking less than 1 inch of water on the magnahelic. Any less and you run the risk of it free flowing in current.
I am a HOG and Deep Six Reg tech instructor and have also written the service procedures for several of the HOG regs. I did write the Deep Six service manual and the DGX manuals for the D6 set, DGX Xtra, and the DGX First reg for suit and pony/stage regs.
I'd also ask why you think this new regs needs a few tweaks? If it was tuned properly when you bought it, it shouldn't need anything. Every reg I sell gets tuned and adjusted according to the factory specs before it leaves. The only exception is some of my tech customers who have experience at rebuilding and tuning regs like to do their own adjustment when they get it. It still gets checked here to verify it meets the specs in the manual though and if something is wonky (sometimes they arrive a little tight or high on the IP by a few PSI, I let them know what I found.
If you don't have experience you're taking a risk. No matter what Alex says. He has some good advice at times and other times, I question his opinion based on my experience.

 

[Nitrox_DiverNY]

Keep in mind that adjusting the orifice with the inline tool directly and profoundly affects lever height. Adjustments that technicians make are in 1/12th of a turn increments (5 min on a clock face).
So if you need to add 1/4 turn to eliminate a freeflow, you may now have a reg whose lever is so low it will not deliver sufficient air at 4 atm (99ft/30m).
And conversely, tuning to the edge of freeflow with your orifice so you can add back resistance with the knob may raise your lever so high that it is pressed firmly against the back of the diaphragm. That may make it unstable in use.
Reg tuning isn't rocket science, but there are quite a few hidden pitfalls (like cutting the seat with the orifice that @stiebs noted above).

Thank you, I will definitely keep this in mind since this is all new to me. I appreciate the help!

 

[Nitrox_DiverNY]

You also need to understand that using the in-line tool should only be used as a last resort on a reg with a few dives on it. You may not hit the groove in the LP seat exactly and start to create another one. Where those intersect you run the risk of leakage.
In addition, if this is a newer Classic or the Zenith second stage on the D3 there is a micro adjust that increases spring pressure without the need to adjust the orifice. The D3 refers to 1st stage only.
There is no D3 second stage.
Also, adjusting the orifice so that the reg just barely doesn't hiss is a bad idea because as the seat wears just a little, you'll have to use the adjustment knob more and more and that in effect reduces the life of the seat. There is no need to have cracking less than 1 inch of water on the magnahelic. Any less and you run the risk of it free flowing in current.
I am a HOG and Deep Six Reg tech instructor and have also written the service procedures for several of the HOG regs. I did write the Deep Six service manual and the DGX manuals for the D6 set, DGX Xtra, and the DGX First reg for suit and pony/stage regs.
I'd also ask why you think this new regs needs a few tweaks? If it was tuned properly when you bought it, it shouldn't need anything. Every reg I sell gets tuned and adjusted according to the factory specs before it leaves. The only exception is some of my tech customers who have experience at rebuilding and tuning regs like to do their own adjustment when they get it. It still gets checked here to verify it meets the specs in the manual though and if something is wonky (sometimes they arrive a little tight or high on the IP by a few PSI, I let them know what I found.
If you don't have experience you're taking a risk. No matter what Alex says. He has some good advice at times and other times, I question his opinion based on my experience.

Thank you for the very detailed reply Jim, it is indeed a D3 first stage with the zenith second stages. I purchased this set from divers supply online and feel that the primary breaths good, but can definitely breath better. I find myself alway having to turn the Venturi all the way up in order to get more are. The octo has a much lower breathing resistance and is much easier to breathe off of when I tried it out underwater. I know divers supply does tune them before sending them out but the primary needs to be tuned a bit more hot for my liking. I appreciate the help and I’ll look into that micro adjust before i make any adjustments with a inline tool

 

[rob.mwpropane]

It's best to only make adjustments whilst there is no pressure on the seat (ie, purge pressed in)

So...do you turn tank on, test, turn tank off, adjust, purge, turn tank on, test, repeat? I don't think I've ever seen it done that way, unless I'm slow and didn't catch it, lol...

 

[rhwestfall]

in-line shut off is a wonderful add-on for a tuning kit...

 

[rob.mwpropane]

in-line shut off is a wonderful add-on for a tuning kit...

That's exactly what I was thinking when I asked the question.