breathing differences in same model reg

[davros]

Hello all,

My daughter is keen to get her OW ticket. She is studying law and arts at Uni, and is coming home for the holidays. I love my daughter dearly (she is my good friend), and it has been a secret wish of mine, that she could be my regular dive buddy some day....... So, I have started to buy some SH gear for her as a surprise for after she completes OW. I am buying gear that is identical or very similar to my own gear for servicing reasons, and two G250's turned up this morning.

I have just finished servicing these G250's, and then tested and all is very good, however I am noticing subtle differences in all of the G250's that I have here at the moment. (6 in total with two mk20's). Some do breathe better than others, and the magnahelic shows differences. I cannot get all of them to breath as well as my favorite G250 primary. To be honest, I wouldn't have had this problem, had you lot not shown me how to service and test my own regs, as I probably wouldn't have noticed too much difference!

Does anyone have any comments?

 

[Texfrazer]

Even though they ar the same model, they are still mechanical systems, and each is prone to find it's own sweet spot.

If you're concerned about breathing effort, swap your primary out for one of the other ones that you're setting up for her, and go diving. You'll be hyper aware of the difference in the beginning, but if you forget about it as soon as you start diving, then "No worries!".

If you feel like it's got a restricted flow, you'll have an excuse to work on the art side of tuning a regulator - which, like other works of art, takes time to develop.

Since you're in the Blue Mountains, you've got some dive spots pretty close by. Another good excuse to pop over to the coast.

Tex

P.S. I love the Blue Mountains!

 

[350xfire]

May breathe better once in underwater as well. The above water testing may not be representative of what it will do at depth.

 

[Davidstealey3]

I have just finished servicing these G250's, and then tested and all is very good, however I am noticing subtle differences in all of the G250's that I have here at the moment. (6 in total with two mk20's). Some do breathe better than others, and the magnahelic shows differences. I cannot get all of them to breath as well as my favorite G250 primary. To be honest, I wouldn't have had this problem, had you lot not shown me how to service and test my own regs, as I probably wouldn't have noticed too much difference!

Does anyone have any comments?

i do have a question with your comment

i am not aware of who made your regs, but did you do a service course with them, or take one offered by air tech?

i read that you said "you would not have this problem had you not shown me how to service and test my own regs". did you follow the advise of people that posted advise on here about how to repair, service and fix them? did you have the service manuels with you when you did the service? did you have the right tools? some of the equipment is manufactor specific, and some of the parts need to go back together in a specific order as not to do damage. if you did not seet the high pressure side right, you could have some pressure creepage. this might be causing some of the differences.

you could also take it to the lds ( if you dont work at one ) and let them take a look.just some advise.

i am no means a pro at this, just started doing repairs this month, so i still have a lot to learn.

 

[Jim Lapenta]

Not a ScubaPro tech even though I will work on the one SP reg I have, but with my oceanics I have noticed minor( very minor differences) due to things like age of the diaphragm, where I set the IP, etc. I have two IP gauges from scubatools and though they usually read the same once in a great while when I'm being really picky I'll notice a 1-2lb difference. Real or just due to environmental conditions, tank pressure, etc. I also have two magnahelics. one reads in millibars and the other inches of water. If it's really humid or really dry they might give a slightly different reading from in the morning, say, to at 6 PM. I would not worry about it. I got SP manuals from frogkick and the ones for my sherwoods as well. Have you tried a simple thing like switching the diaphragms from one to the other and see if it makes a difference. Just some thoughts.

 

[davros]

Hi Guys, and thank you for the comments.

And below.... Good questions David.

i am not aware of who made your regs, but did you do a service course with them, or take one offered by air tech?

I did do a service course with Scubapro back in 1995. It was run by the area sales rep for SP, and It cost a packet of money, paid for by my brother who owned a dive shop back then. The course was a teaser IMO, and dealt with two specific regulator combinations.... d400 and g200 with mk10 1st stages. I would not recommend anyone bothering with a course like that. Far better off reading Vance's book. SCUBA REGULATOR MAINTENANCE AND REPAIR by Vance Harlow

i read that you said "you would not have this problem had you not shown me how to service and test my own regs". did you follow the advise of people that posted advise on here about how to repair, service and fix them?

The comment in the first sentence was meant to be a friendly joke. Australian humour is lost on some. In answer to the question.... yes I did follow advice given on this board.
Thanks again to all who have contributed over the years!

did you have the service manuels with you when you did the service?

Yes.

did you have the right tools?

Yes.

some of the equipment is manufactor specific, and some of the parts need to go back together in a specific order as not to do damage. if you did not seet the high pressure side right, you could have some pressure creepage. this might be causing some of the differences.

Yes, I now have a very good array of regulator specific tools, and no, I didn't damage the high pressure seat or o-ring. I have the piston assembly tool and bullet, and I know how to use them.

you could also take it to the lds ( if you dont work at one ) and let them take a look.just some advise.

No, they are the ones that hacked up one of my expensive regs, and then justified thier lack of competence by saying that the yoke nut is supposed to be hacked up over time when serviced. They offered to replace it for $85.00 though. Note: these regs have never been as good as they are now, being serviced by the LDS up until now. I am not getting any creepage at all at surface. I haven't tested the regs in the water yet.

My original post was just me in my musings mode, (AKA mild mental disorder) about the differences with one identical reg over the other. Both serviced at the same time, using identical parts and techniques. There isn't that much difference really. EG: the best breathing G250 reg is set to crack at 0.8 inches, and the worst is set at 1.3 inches. The reg that is set at 1.3 will not go any lower without leaking. When testing, I had all four second stages hooked up to the one first stage. (Mk20 just serviced, and ip set at 138lbs with 2x .012" shims outside, and three inside.)

Thanks again.

 

[Davidstealey3]

i guess the shop the dinged up your yoke nut, was using the wrong tools. its like people theat use the wrong spanner wrench, and dont have tape to protect the reg, or use an old diaphram either. oh well what are you to do.

i agree with you, the manufactor specific course are a little vauge, but at least you can get free repair parts out of the deal sometimes.

i do want to take a nice three day course one day to learn how to use the magnahelix, and some of the other tricks of fine tuning regs.

 

[NJDiver07866]

Hello mate,

I'm pretty good with tuning the G250. First question and sorry for asking, just have to start with the basics... are they all the same model? The G250 has the brass air tube, the G250HP has the plastic and G250V (vintage) introduced in 2008 they went back to brass. In each model they have a slightly different. The HP has even a very slight different case. In every model even the lever is slightly different.

Ok once this is out of the way and you are comparing apples to apples...
I tell you what.. I had a heck of a time with the two poppet o-rings.. the real tiny ones. Even if there is the smallest leak it will cause the reg to breath like ****e...if they don't seal the concept of the balance chamber pretty much gums up the works.

Also look at the seat and if they are made by the same factory. I got a bunch of rivit seats from Trident and they have a slightly smaller hole than the ones that come in the SP kits... Also new seats don't have that cookie cutter ridge cut in them from the orifice. I noticed it takes a few dives to get the seat 'broken in". So I usually set them up once after an overhaul, dive them a few times and then go back for one last adjustment. I know my shop will just set them up 'tight' in anticipation for the seat to break in, because they don't want to adjust in again when it breaks in, but I like to tinker so I adjust it once after a new seat, dive with it and then just adjust it again....just food for thought...

Check the balance chamber for cracks/wear.. thats the tiny bucket thing that goes on the end of the poppet and is sealed with those two pesky o-rings. I had one that was bad and it drove me nuts. Only after taking it to my regulator god/mentor (the guy is like 70 and can hardly see) he pointed out that the plastic balance chamber sometimes get damaged or get "out of round" or wear out over time since they get rubbed against constantly by the poppet o-rings. The SOB was right.. I looked at the balance chamber hole and it was almost egg shaped. So I had to go w/ my tail between my legs and ask my SP dealer for a balance chamber. Luckly the girl behind the counter had no idea about the James bond 007 spy network of getting parts So I just picked out the part and she asked me how much it was and I told her $3.50 and I had a new part.

last but not least the spring on the poppet. I noticed these can vary and wear out with time. I think there is a way to measure the 'springyness' of them, but I just get around this by adjusting it tighter. I can tell you on the S550 and the S555 I have one weak spring and one strong spring and it does make a difference in adjusting the regs for breathing...

well good luck... I shared my gray matter.. hope it helps....dive safe

 

[davros]

Hi NJDiver07866,

Thanks very much for sharing your grey matter. You have added to mine!

First question and sorry for asking, just have to start with the basics... are they all the same model? The G250 has the brass air tube, the G250HP has the plastic and G250V (vintage) introduced in 2008 they went back to brass. In each model they have a slightly different. The HP has even a very slight different case. In every model even the lever is slightly different.

All of the regs are original G-250's. I have had 4 of them since new, and they have been great. I just picked another two the other day, that are in good used condition. All regs are identical, except the two used ones, have different colored poppets. Same shape, just different color. FWIW, although the G-250HP is supposed to be better because the HP stands for High Performance.... (all according to an acquaintance that has them and thinks they are far superior to the original).... I disagree. I have dived both, and like mine better, especially at depth.

Your comments on the poppet O-rings caught my eye. When I installed them, I just put a touch of Cristolube 111 around them. Going back to Vances' book, he sort of states that they should be masturbated a little, while in position, before installing the poppet assembly. The other comments you gave, have been covered.

Anyway, I am doing charity fete work today and tomorrow so won't get a chance to fiddle with it for a couple of days. I will report back if the masturbation was successful.

Thanks very much for your input.

 

[redacted]

What color poppets are you talking about? I have seen grey plastic with the metal stem and blue plastic with the metal stem, both of which are now obsolete. Current s-wing poppet is one piece white plastic with 2 balance chamber o-rings (original had only one o-ring). How much of a difference are you talking about on the magnehelic? Some small differences are almost bound to occur as a function of the condition of the orifice knife edge and the interface of the lever with the diaphragm. Plus I'm sure that there must be acceptable variances in the LP seat specs that would cause small performance differences. I noticed mores differences in performance in my Subapro R-series than in the barrel popper designs although I do see a bit of variance in my 109s.