Advice on servicing my own regs....

[sambolino44]

No, the reason for the IP check at both low and high tank pressure is to check for IP stability...

I don't think so. I think it's more likely for one of the reasons in my earlier post, which you quoted, but don't seem to have read. It's not that I disagree that checking the IP at both low and high pressures is a good idea, it's that the manual is very careful to make sure that the reg is brought up to pressure very, very slowly.

...The reg that you're referring to (IP 120@500PSI, 135@3000) could only be an unbalanced piston reg...

It's a U.S. Divers SEA balanced diaphragm. It doesn't say to adjust it so that it has an IP of 120@500psi after you're done, only as a first step in the process. After I finished the procedure in the book, I went ahead and hooked it back up to the 500psi tank, and the IP was still at 135.

...there's nothing wrong with connecting a newly serviced reg to a full tank and simply opening the valve slowly while holding down the purge valve slightly. IOW, you can be gentle with a full tank. If there's a serious problem with the HP seat and you get HP air leaking into the IP chamber, you're going to know very quickly and be able to shut the valve off.

I appreciate everybody trying to help, but it kills me the way so many people seem to be so sure that they know more than the manufacturer about how to set up this reg. I understand that often there are other considerations, like safety, liability, etc. It just kills me how people read something they don't quite understand, and instead of saying, "hmm, I wonder why they do it that way?" they jump right past that and into, "Oh, they don't have to do that. You can skip that step."

I'm just suggesting the possibility that there is actually a good reason to do it this way that maybe we haven't thought about. Or maybe not. But it wasn't that big a deal to have both an empty and a full tank available when I did my adjustment, and I was just suggesting that maybe the OP might want to consider that he might want to be prepared before he starts the job.

 

[redacted]

I don't think so. I think it's more likely for one of the reasons in my earlier post, which you quoted, but don't seem to have read. It's not that I disagree that checking the IP at both low and high pressures is a good idea, it's that the manual is very careful to make sure that the reg is brought up to pressure very, very slowly.



It's a U.S. Divers SEA balanced diaphragm. It doesn't say to adjust it so that it has an IP of 120@500psi after you're done, only as a first step in the process. After I finished the procedure in the book, I went ahead and hooked it back up to the 500psi tank, and the IP was still at 135.



I appreciate everybody trying to help, but it kills me the way so many people seem to be so sure that they know more than the manufacturer about how to set up this reg. I understand that often there are other considerations, like safety, liability, etc. It just kills me how people read something they don't quite understand, and instead of saying, "hmm, I wonder why they do it that way?" they jump right past that and into, "Oh, they don't have to do that. You can skip that step."

I'm just suggesting the possibility that there is actually a good reason to do it this way that maybe we haven't thought about. Or maybe not. But it wasn't that big a deal to have both an empty and a full tank available when I did my adjustment, and I was just suggesting that maybe the OP might want to consider that he might want to be prepared before he starts the job.

Scubapro TSM calls for an IP check at 3000 psi and at 500 psi for piston 1sts in no particular order. My manual does not address BDs.

 

[captain]

Just about all of my regulators use the same first stage as the SEA and I have never had any issues putting it on a full tank initially.
Actually I prefer to tune them by balancing IP against 2nd stage spring force and use whatever IP accomplishes that.

 

[LeadTurn_SD]

I appreciate everybody trying to help, but it kills me the way so many people seem to be so sure that they know more than the manufacturer about how to set up this reg. I understand that often there are other considerations, like safety, liability, etc. It just kills me how people read something they don't quite understand, and instead of saying, "hmm, I wonder why they do it that way?" they jump right past that and into, "Oh, they don't have to do that. You can skip that step."

I'm just suggesting the possibility that there is actually a good reason to do it this way that maybe we haven't thought about. Or maybe not. But it wasn't that big a deal to have both an empty and a full tank available when I did my adjustment, and I was just suggesting that maybe the OP might want to consider that he might want to be prepared before he starts the job.

Hi sambolino44,

Lets look at a few manuals (including the Conshelf XIV which I highlighted since it should be the procedure you use for the SEA) and try to figure this out so nobody loses sleep:

*********************************************

Conshelf XIV:

While watching the intermediate-pressure gauge on the test bench, slowly pressurize the bench and regulator to 500 psig. The intermediate-pressure gauge should indicate a “lockup” pressure of 120 to 160 psig. If the gauge pressure increases beyond 160 psig, turn the air source off immediately. This indicates a failure of the first-stage regulator to achieve “lockup” pressure. Refer to the Troubleshooting Table 1 on page 14 for corrective guidelines and specific procedures.

.....After stabilizing the intermediate-pressure repeat Steps 2 through 5 at 3000 psig, service pressure.

Scubapro Mk20:

Check the intermediate pressure using the pneumatic adjusting tool.
Intermediate pressure range: 125psi to 145psi at 3000psi and 300psi supply pressure.

Zeagle Regulators:

Attach the regulator to a tank valve giving a source pressure of between 2700 and 3500 psig (186-240 Bar). Turn the supply air on slowly while listening for any unusual air leaks. If any are heard, turn the air off immediately and determine the source of the leak. If no leaks are found, watch the intermediate pressure gauge reading rise as you continue turning the air on slowly. It should stop before 145 psig (10 bar) since the intermediate pressure has not been set yet. If the pressure gauge continues to rise above 155 psig (10.4 bar), turn the air supply off immediately and inspect the regulator to determine the cause.....


Mares Regulators:

Similar to Zeagle. Bring pressure up carefully, test IP at 2,000 to 3,000.

**************************************

Again, although the procedure varies widely between brands, my opinion based on reading these and several other manuals is that bringing the pressure up slowly is primarily for safety. I think the Conshelf / SEA uses the most conservative procedure of the regs I've seen (which I admit are very few compared to a lot of folks on this board).

It looks like the Conshelf / SEA manual wants to see stability at 500 lbs first before moving forward, to make sure that assembly was performed correctly. And I believe the Conshelf / SEA specifies the 500psi --> 3,000psi sequence for all of it's adjustment steps. As with other brands, they want you to cycle the reg by hitting the purge a few times to check for stability of the IP, and if course you need to do this as you change the IP setting.

Other brands seem totally ok with just bring up the pressure slowly to 3,000 psi and making sure a 2nd stage is attached as a "safety relief valve" just in case.

Again, this is just how I'm reading the manuals. I'm far from an expert. But testing at low and high pressure seems to be looking at overall stability of the IP at different supply pressures, and starting from low pressure and working to high pressure seems to be primarily for safety.

So, in the case of the Conshelf / SEA, or any other reg that actually requires that the IP be stabilized at low pressure 1st, then at high, and possibly again at low for further adjustment steps it would make sense for the DIY tech to have two tanks. One at 500psi, one at 3,000psi (or whatever the manual calls for).

Ok, I can sleep now.

Best wishes.

 

[halocline]

I don't think so. I think it's more likely for one of the reasons in my earlier post, which you quoted, but don't seem to have read.

Oh, I read your post, it was just wrong for the reg under discussion (SP MK16) so I disagreed with it.

But I did misread your bit about the 120-135 IP at low and high tank pressures. You're setting the IP twice; first at 120, then at 135. That's not done for SP regs, which is where this thread started.

 

[sambolino44]

Fair criticism and points well made.

I do want to re-emphasize to the OP, however, that making sure you have everything you'll need before you start is a good idea.

 

[DA Aquamaster]

On an unbalanced piston reg checking there IP at the high and low end is important as there is a significant drop in IP with 3300 to 300 psi supply pressures. But it is also pretty linear. After doing a gazillon Mk 2's even the slowest tech figures out if the IP is less than about 140 psi at 3000-3300 psi, it will fall out the bottom end of the acceptable range at 300-500 psi, and over time you get pretty good at estimating the IP at each end if your supply pressure is somewhere in the middle - say 1900 psi.

More importantly, you need to adjust the second stage at the maximum IP. Otherwise if adjusted at the low end, it may freeflow at higher tank pressures due to the higher IP.

 

[Couv]

On an unbalanced piston reg checking there IP at the high and low end is important as there is a significant drop in IP with 3300 to 300 psi supply pressures. But it is also pretty linear. After doing a gazillon Mk 2's even the slowest tech figures out if the IP is less than about 140 psi at 3000-3300 psi, it will fall out the bottom end of the acceptable range at 300-500 psi, and over time you get pretty good at estimating the IP at each end if your supply pressure is somewhere in the middle - say 1900 psi.

More importantly, you need to adjust the second stage at the maximum IP. Otherwise if adjusted at the low end, it may freeflow at higher tank pressures due to the higher IP.

…..and a good reason to have an adjustable, or even better, a balanced adjustable second stage. One of the most overlooked first and second stage combinations available, and a for the money one of the best. (Unbalanced piston coupled with an adjustable second stage)

Couv

 

[USFishin]

About 6 months ago I had my first experience at servicing regulators. I have 2 Oceanic Delta 3 sets, my wife has a Delta 4, and two of my friends have Delta 4's. So we figured that if we split the cost of the tools between us it wouldn't be too expensive. The tools ended up being around $150 or so. The only real specialty tools we purchased were the poppet tool and the spanner wrench tool. We got a brand new ultrasonic cleaner from ebay for around $35. We bought a tube of Christolube too. We made an IP gauge by purchasing the gauge from Northern Tool and getting the BC hose adapter from Scubatoys and a coupler from Home Depot. I had some dental pics for removing the o-rings.

It was actually pretty easy. The main reason we wanted to do it ourselves was peace of mind knowing that we did everything to spec and all of the parts were fully cleaned before reassembly. My buddy had a reg "rebuilt" at a local shop that we disassembled and we were amazed at how bad and corroded it was inside. Needless to say he won't be having any gear serviced at that shop anymore.

After you've serviced a reg or two you will definitely want to service your BC inflator valve. It's a piece of cake compared to the reg. Another specialty tool you'll need though is a schrader valve tool (the same valve that's in a bicycle/car valve). The one I got on ebay was nice because it came with 4 different sizes which came in handy. My wife's BC valve was a little larger than mine was so luckily I had the correct size tool.

I do have a question for some of you more experienced rebuilders out there. The service manual instructs you to install the LP seat into the Poppet so that the shiny side is out (the side that contacts the Orifice). Does this really make a difference? And if not, why couldn't you just flip the LP seat around and use the back side of it when the front side wears out (the Orifice wears a circular line into the LP seat)?