Question Skipping 1st stage Maintenance?

[L13]

You use an inline tool to adjust the second stage, when mix matching brands. Plenty of youtube vids.

If both 1st's are at the same IP, (or even close, for balanced 2nd's) there is no need to adjust the 2nd's.

If you are only doing it a few times a year, no need for an inline adjuster. It speeds up the process, but isn't necessary.

Brand has no relevance, the second stage is tuned to the IP of the 1st, not the brand, model, or serial number of the 1st.

 

[lexvil]

Generally speaking with “most” first stages operating in the same IP range you can switch balanced seconds with little to no difference in breathing.

your initial mention of how poorly the seconds are breathing is of more concern so some elaboration would be handy.

 

[MidOH]

If both 1st's are at the same IP, (or even close, for balanced 2nd's) there is no need to adjust the 2nd's.

If you are only doing it a few times a year, no need for an inline adjuster. It speeds up the process, but isn't necessary.

Brand has no relevance, the second stage is tuned to the IP of the 1st, not the brand, model, or serial number of the 1st.

I agree.

But taking the time with an inline tool was worth it. You're almost proof testing the complete reg system at that point.

If it still breaths poorly after that, it's got issues and needs rebuilt by a pro.

 

[Pearlman]

Generally speaking with “most” first stages operating in the same IP range you can switch balanced seconds with little to no difference in breathing.

your initial mention of how poorly the seconds are breathing is of more concern so some elaboration would be handy.

Well it’s now 4 weeks since my last dive trip but IIRC the cracking pressure and W.O.B was too high almost like there was some kind of blockage. The air was too thin… and for some reason I was dissatisfied even after turning the knob all the way and when I did it free-flowed rather easily. But my recollection is vague now as after the first two days of diving I switched to the C370 as the primary for the next 10 days - which was relatively unused till now (only 14 dives) and its a beauty of a reg!

For rec diving. I have an inline IP guage and tuner, and another little IP guage in my reg bag.

I missed this bit - What’s a Tuner?

The 1st and 2nd stages need to be tuned as a set. IP variations may result in variable performance when swapped around. This will get worse over time as they slowly get out of tune…

Another question - is it possible to tune both MK25 and the MK19 Evos to the same IP? That would solve the issue of swapping regs …

 

[lexvil]

Well it’s now 4 weeks since my last dive trip but IIRC the cracking pressure and W.O.B was too high almost like there was some kind of blockage. The air was too thin… and for some reason I was dissatisfied even after turning the knob all the way and when I did it free-flowed rather easily. But my recollection is vague now as after the first two days of diving I switched to the C370 as the primary for the next 10 days - which was relatively unused till now (only 14 dives) and its a beauty of a reg!

I would hope that some tuning may do it but just not enough info to make a guess.

 

[elmo]

Well it’s now 4 weeks since my last dive trip but IIRC the cracking pressure and W.O.B was too high almost like there was some kind of blockage. The air was too thin… and for some reason I was dissatisfied even after turning the knob all the way and when I did it free-flowed rather easily. But my recollection is vague now as after the first two days of diving I switched to the C370 as the primary for the next 10 days - which was relatively unused till now (only 14 dives) and its a beauty of a reg!



I missed this bit - What’s a Tuner?



Another question - is it possible to tune both MK25 and the MK19 Evos to the same IP? That would solve the issue of swapping regs …

Not only can they be tuned to the same IP, they *should* be tuned to the same IP range of 9.2-9.8 bar (133-142 psi). With balanced second stages like you have I doubt anyone could tell the difference between the upper and lower limits.

 

[L13]

Unless you feel mechanically inclined or wish to take a little training, I don't recommend you get the inline adjuster or do any tuning other than the fine adjustment knob. One of the biggest risks in doing your own 2nd stage maintenance is doing the tuning wrong, dropping the lever height, and not getting enough gas flow at depth. Most other errors are obvious at the surface.

Both regulators 1st stages should already be at the same IP unless they need maint. Swapping regs should not be a problem.

 

[davehicks]

Swapping regulators should not be a problem - unless it is. You need to learn a bit more about your gear, how to measure and test, and how to tune it if you want to be doing this. This unnecessary and problematic thing of moving your seconds all the time.

Yes, it can be done but should it? Really?

 

[MidOH]

Second Stage In-Line Adjusting Tool w/IP Gauge

The 2nd Stage In-Line Adjusting Tool is used for fine tuning regulator 2nd stages which have an adjustable air inlet orifice. The tool also has a built-in pressure gauge which allows the intermediate pressure (IP) of the 1st stage to be checked.

www.divegearexpress.com

This is the inline tuner that I used to put Dive Rite Xt4's on a leftover Hog D1 yoke reg.

Really was nothing to it. (So far) Likely wasn't needed. Just gives me an option to set the longhose kinda loose, and the necklace a little tight.

 

[Still Kicking]

What you can also do is to remove hoses and all plugs and take a look inside for quick visual check. If they look clean, chances are it's all fine.

Excellent point. Take the hose off the second stage -- look inside the inlet. If anything made it into the first stage it will generally build up at the second stage orifice.