Problems with serviced regulators

[drcolyn]

Some 10 years ago I had the idea of cutting down on the annual servicing cost of my Apeks T20 regulator. Since the second stage leaked air for a couple of dives after each service I naively thought I can procure service kits directly from Apeks and do a better job myself. Needless to say Apeks did not agree and told me to take my regulators to a “qualified service technician” since I did not have all the expensive testing equipment required for the job. Since I have worked at a shop that repaired truck air brakes I know the value of a test bench but if scuba regulator service is such an exact science, then why was mine leaking air?

3 Years ago I sold the Apeks and bought new (cheaper to service) Scubapro first stage MK17 and R395 second stage with R295 octo. Last month I had the set serviced for the first time (just as a precaution) and the first two dives were terrible. The air from the R395 was so wet (like when you breathe air from a humidifier) that it made me cough for two hour long dives. I took it back to the shop that serviced it but they could not find a problem with the mouthpiece or the exhaust valve or a crack in the housing. The technician reckon it could be that I “flooded the dv” during the entry. I am not bothered by a little water in a DV – I mean I don’t even use the purge button to clear my dv after took a drink of fresh water during a dive.
The R295 octo was breathing dry although I must mention I had that connected to my bail out cylinder so I am not sure if my main cylinders had water in them that could been the source of the moisture. They were filled by a testing station that did the visual inspection so I find it hard to believe that they would fill with wet air knowing what damage it causes (although… this testing station does have a reputation for doing chemical cleaning at the slightest sign of rust)
Some weeks ago I bought a second hand 1^st generation MK25 first stage and had that serviced by the same shop. When I did a dry test the 1^st stage was making a strange shrieking sound. I spoke to the technician today (having read this may be due to a high pressure piston O-ring not being lubed properly) and he said it may be a “misaligned O-ring” during the assembly process and that I must take it for a test dive “but not a deep dive” and if the shrieking sound continue I can bring it in for a free checkup.

Now I would love to hear from some “qualified technicians” if I am being overly harsh or do I have the right to question why these problems were not picked up on “the test bench”.

 

[redacted]

I am not a "qualified technician".

Excessively wet breathing is not normal. Did the tech conduct a vacuum check? Besides the exhaust valve, case, and mouthpiece; there are a couple case sealing o-rings that could cause such a problem. A vacuum check would confirm or disprove the leak.

Noise coming from a first stage is not normal but also not unheard of. Usually a problem with a dry or extruding dynamic HP o-ring. A fluttering sound on exhalation from a 2nd stage may occur in a dry test but should should disappear when the water dampens the vibration UW.

You need to insist that the tech repair both problems or refund the cost of then service.

 

[Wayne at DiveSeekers]

I could only guess that when they assembled it, the manual gives guidelines/specs to put it back together, once done, reg was bench tested (maybe) once for IP and cracking effort and then put on the shelf as done. When we are done assembling the reg we put the reg on the bench test and cycle (purging the second stage) it, probably around 200 times. With this approach, it gives a chance for new parts/lubricants to brake in and you will either find out about potential problems (ip holding, with materials in parts kit or something put back wrong) or it will just confirm that it is in perfect working order.

Try to test out reg when you pick it up. one way to test second stage is to inhale on it when not on tank. When you suck in, you should get nothing, if you hear air, something is wrong.

A lot of time harmonics in the first stage can be that the spring has to get flipped.

 

[kwinter]

And a lot of times a reg that is serviced will operate and breathe perfectly on land. Of course it can't possibly breathe wet in those circumstances. The only test that counts is underwater. The time you are most likely to have a problem with a regulator is immediately after service, whether you do it yourself or let a pro handle it.

 

[Couv]

I am not a "qualified technician".......

I have to disagree with you on the above. Certified does not equal Qualified. I consider you very qualified. One does not need to be certified to be qualified.

You need to insist that the tech repair both problems or refund the cost of then service.

What he said.

 

[halocline]

Try to test out reg when you pick it up. one way to test second stage is to inhale on it when not on tank. When you suck in, you should get nothing, if you hear air, something is wrong.

A lot of time harmonics in the first stage can be that the spring has to get flipped.

You're right about the vacuum test; if you cannot pull any air in then it's very unlikely the reg will breathe wet. This is the way you test for leaks in the ambient pressure chamber of the 2nd stage, which are what would allow water leak in. Anything upstream of the 2nd stage valve is under pressure, and you check for those leaks by pressurizing the reg and submerging it in water, and listen for the bubbles. An alternative test is to pressurize the reg, then turn off the tank but leave the reg under pressure and watch to see if the SPG slowly heads towards zero. But this doesn't help you isolate the leak.

Regarding the noise, if the first stage is making the humming (not really shrieking) it is almost certainly a poorly lubed o-ring that is transmitting vibrations from the piston to the spring. "Flipping the spring" doesn't really fix the problem, although often when someone does this, they also re-lube the o-ring and re-set the bushings, and for whatever reason, the resonance is broken.

More of a honking sound (like a terrible sax player, I've met a few of those) might be the 2nd stage diaphragm resonating, and that always goes away under water. The water dampens the vibration. Hey, maybe that would work for the bad sax players, too!

To the OP; start learning to service your own regulator, there are lots of people on this forum that can help you, you can probably find a local mentor, and scubapro parts are not difficult to find from alternative sources like ebay.

 

[Bob DBF]

To the OP; start learning to service your own regulator, there are lots of people on this forum that can help you, you can probably find a local mentor, and scubapro parts are not difficult to find from alternative sources like ebay.

Yeah, what he said.

drcolyn, you already got the A-team answers, I'll just toss in my two cents as one who works on old Sherwood's and antiques.

If you service your own reg you don't have to argue with a shop tech about who caused the problem or who has to fix or pay for more service. Also I, since I do my own regs, I do a pool test, then a full tank tank in shallow (30-60') water test, and finally a 120' or so deep test. Try to find a shop that checks the actual operation of a reg in actual conditions. I haven't had a reg puke on me without a lot of warning. If my daughter grabs a reg off my shelf, I don't worry about her having a problem with the reg.

It's not that all techs are sloppy, or they should do in water tests, but if your regs are not given to you in good order, you should look for another tech, or start picking up tools and learn how to use them. I, personally, feel that regs should come back good to go, or the tech should be very imbarresed and apologetic that he, or she, made an error.

Regulator service is not rocket science, anyone with mechanical aptitude and the ability to read instructions can be quite successful, otherwise I would have been in deep s**t a long time ago. I did send the old ('70's/'80's) Poseidon I picked up out for service because I didn't have a clew, however the tech and I had a long chat about how to service the reg and I would have been way over my head because they don't work quite the same as what I am used to. I might try the adjustment next time because of his advice, but I still did my in water checks when it was returned and it worked flawlessly.



Bob
---------------------
I may be old, but I'm not dead yet.

 

[drcolyn]

Thanks to all those that replied. I especially liked the encouragement to go DIY - I'm sure that will agitate the scuba engineers.
Just to answer some questions - I ALWAYS do a dry test at home before I go for a dive (UW photography = solo diving and I do not take my safety for granted)
I mentioned the dry test so that you know I understand the vacuum test concept and the fact that pluttering exhaust valves disappear in an underwater test. After getting the R395 and R295 back from the shop I did the vacuum test and found nothing extraordinary - I would even go so far as to say that the R295 octo (which breathed dry under water) seemed to be leaking vacuum slightly through the exhaust valve when I sucked really hard. Something else I noticed was that the moisture in the regulator did not leave me with a salty mouth but it persisted in the regulator no matter how hard I tried to blow it out. Because I am so anal about my equipment I have never dived with a broken mouthpiece before so I don't know if this type of leak is supposed to taste salty. Don't know maybe I was drooling into the regulator because the visibility was so good but I still wonder if the source of the moisture did not come from the cylinders. Both were filled at the same time when they went for visual inspection. I would really appreciate if someone who has had the experience of a very wet air fill (say a dodgy dive operator who worked his compressor triplex filter into overtime to save money) can comment and let me know if it felt like breathing air from a humidifier.

As for the MK25 that is playing sax badly - the tech said I should not worry since there are two O-rings on the hp piston in case the one goes - I don't find that funny at all since this regulator is on my bail out cylinder and I paid with a credit card that works faultlessly every time. According to the tech it seemed fine when he tested it (maybe the compressor was running in the background). To their credit they never haggled or refused to open a regulator and take a second look but what annoys me (apart from risking my life on iffy equipment that I took for a service in time) is the fuel cost. It is a 300km trip to the dive shop and back. Hence me asking if there was any reason why this problem could not have been detected during testing?

As for the DIY option - we have the scuba Mafia in RSA. You are blissfully unaware of their existence until you try to buy Suunto or Scubapro products on the internet because they are 50% cheaper than in the local shops. Then you get the bad news – they are not allowed to sell to the African continent because the scuba mafia has a “service agreement” which makes them the sole supplier in Africa. If someone can send me links of those that will defy the mafia I would not mind trying to buy the kits myself.

 

[Zung]

... As for the MK25 that is playing sax badly - the tech said I should not worry since there are two O-rings on the hp piston in case the one goes...

Nope, not the piston crown O-rings; it's the HP O-ring (2-010, duro 90, Viton, PU or EPDM) on the piston stem which is nicked. I reported a similar case here. It's not hard at all to replace it yourself.

And yes, it may happen all of a sudden: the O-ring could be half nicked for any reason but can still survive a few blast in the shop, until it finally gives in after you drive 150 klicks back. Very bad karma.

 

[halocline]

As for the MK25 that is playing sax badly - the tech said I should not worry since there are two O-rings on the hp piston in case the one goes -

That guy needs to repeat the extremely demanding and rigorous SP training seminar.