Another possibly reason why Positive & Negative test fails

Michael Jensen · 11th August 2008, 18:23

Hello All

Just want to inform those of you that struggles with Positive & Negative test, about another possible reason to the problem.

This weekend I found another reason, causing this problem. My unit is a little over a year old now, and has never had any problems holding positive & negative test, even for 24hrs. But during the recent divetrip to Iceland, it became more and more leaky.
I did a disassembly of all hose connections and T-pieces,, and cleaned and greased everything, but that did not solve the problem. I did my diving without any problems during the trip, since the leak wasn´t that bad that there was anything bubbling in the water. But that leak really pi...d me off!
So, there was only one thing to do when we came home,
start from scratch again...

And by accident I found the problem. the port in the counterlung where the O2-inflator button are screwed into was loose!
I actually unscrewed it when I screwed the O2-inflator into the port, because the port has left-hand thread in the counterlung.
So I was of course curious about the other port for the Diluent inflator...
Almost as loose as the O2 inflator!

I have maybe been causing the leak myself, by tightening the Inflator buttons to hard sometimes.

But these ports might be worth checking, if any of you are experiencing strange leaks.

Michael

diverberr · 11th August 2008, 18:55

Michael,

This was one of the things I was warned about by my instructor. Not to overtighten the inflators or you will loosen the fitting in the counterlung. I haven't had problems with mine, but because I was told about it early on, it's something I'm always mindful of when assembling the unit.

Cheers,
Al.

Michael Jensen · 11th August 2008, 20:25

Quote: (Originally Posted by diverberr)

Michael,

This was one of the things I was warned about by my instructor. Not to overtighten the inflators or you will loosen the fitting in the counterlung. I haven't had problems with mine, but because I was told about it early on, it's something I'm always mindful of when assembling the unit.

Cheers,
Al.

Hi Al

I was also informed of this by my instructor, and have always taken care when tightening the inflator buttons, but over the time, I have managed to loosen the ports a bit. The unit is performing the pos & neg test perfectly again!

ATB
Michael

Captain Nemo · 11th August 2008, 20:42

If you keep the mounting O ring lubricated , the inflator will swivel easily... and not the fitting...

Dave Faye · 14th August 2008, 13:00

I have not had too many issues with failed neg/pos test. However, after a few years of diving on my unit, I can say that almost every failed neg or pos test I have had was at the connection point between the manual dil or 02 inflator. I always check here first when I have a failed test. Toss your unit in the bath and look for bubbles. You don't even have to fill the tub since the manual inflators are low on the C/L.

If you don't already have one, buy a 1/2 inch hex key and put it in your tool kit.

cubixy2k · 14th August 2008, 15:03

Had the same issue with my unit a couple weeks ago.
Thought I tightened it enough then after a loop flood I learned I didn't.

Luckily I was in the quarry at shallow depths, I just aborted the dive and surface swam in, no problems, but definitely raise concerns.

Now I do my pos test and submerge it in water to look for leaks.

11th August 2008, 18:23	#1 (permalink)
Michael Jensen New Member Current Rebreather/s: Inspiration Vision Other Rebreather/s: Join Date: Aug 2006 Location: Denmark Posts: 15	Another possibly reason why Positive & Negative test fails Hello All Just want to inform those of you that struggles with Positive & Negative test, about another possible reason to the problem. This weekend I found another reason, causing this problem. My unit is a little over a year old now, and has never had any problems holding positive & negative test, even for 24hrs. But during the recent divetrip to Iceland, it became more and more leaky. I did a disassembly of all hose connections and T-pieces,, and cleaned and greased everything, but that did not solve the problem. I did my diving without any problems during the trip, since the leak wasn´t that bad that there was anything bubbling in the water. But that leak really pi...d me off! So, there was only one thing to do when we came home, start from scratch again... And by accident I found the problem. the port in the counterlung where the O2-inflator button are screwed into was loose! I actually unscrewed it when I screwed the O2-inflator into the port, because the port has left-hand thread in the counterlung. So I was of course curious about the other port for the Diluent inflator... Almost as loose as the O2 inflator! I have maybe been causing the leak myself, by tightening the Inflator buttons to hard sometimes. But these ports might be worth checking, if any of you are experiencing strange leaks. Michael
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11th August 2008, 18:55	#2 (permalink)
diverberr New Member Current Rebreather/s: Inspiration Classic Other Rebreather/s: Join Date: Oct 2005 Location: Eastern Passage, Nova Scotia Posts: 42	Re: Another possibly reason why Positive & Negative test fails Michael, This was one of the things I was warned about by my instructor. Not to overtighten the inflators or you will loosen the fitting in the counterlung. I haven't had problems with mine, but because I was told about it early on, it's something I'm always mindful of when assembling the unit. Cheers, Al. __________________ www.wreckdivingtales.com
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11th August 2008, 20:25	#3 (permalink)
Michael Jensen New Member Current Rebreather/s: Inspiration Vision Other Rebreather/s: Join Date: Aug 2006 Location: Denmark Posts: 15	Re: Another possibly reason why Positive & Negative test fails Quote: (Originally Posted by diverberr) Michael, This was one of the things I was warned about by my instructor. Not to overtighten the inflators or you will loosen the fitting in the counterlung. I haven't had problems with mine, but because I was told about it early on, it's something I'm always mindful of when assembling the unit. Cheers, Al. Hi Al I was also informed of this by my instructor, and have always taken care when tightening the inflator buttons, but over the time, I have managed to loosen the ports a bit. The unit is performing the pos & neg test perfectly again! ATB Michael
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11th August 2008, 20:42	#4 (permalink)
Captain Nemo RBW Member Current Rebreather/s: Evolution Other Rebreather/s: Not Bought Yet Inspiration Classic Inspiration Vision Evolution Megalodon Sport Kiss Classic Kiss Join Date: Oct 2006 Location: CORNWALL Posts: 55	Re: Another possibly reason why Positive & Negative test fails If you keep the mounting O ring lubricated , the inflator will swivel easily... and not the fitting... __________________ Look beyond the dark side into the light. Beware of false knowledge; It is more dangerous than ignorance.
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14th August 2008, 13:00	#5 (permalink)
Dave Faye Know the wreck below? Current Rebreather/s: Evolution Other Rebreather/s: Inspiration Classic Evolution Megalodon Join Date: Oct 2005 Location: Boston Posts: 169	Re: Another possibly reason why Positive & Negative test fails I have not had too many issues with failed neg/pos test. However, after a few years of diving on my unit, I can say that almost every failed neg or pos test I have had was at the connection point between the manual dil or 02 inflator. I always check here first when I have a failed test. Toss your unit in the bath and look for bubbles. You don't even have to fill the tub since the manual inflators are low on the C/L. If you don't already have one, buy a 1/2 inch hex key and put it in your tool kit. __________________ Dave http://www.Bostondeepwrecks.com http://www.Fayelaw.com
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14th August 2008, 15:03	#6 (permalink)
cubixy2k RBW Member Current Rebreather/s: Evolution Other Rebreather/s: Evolution Join Date: Dec 2007 Location: Philly Posts: 65	Re: Another possibly reason why Positive & Negative test fails Had the same issue with my unit a couple weeks ago. Thought I tightened it enough then after a loop flood I learned I didn't. Luckily I was in the quarry at shallow depths, I just aborted the dive and surface swam in, no problems, but definitely raise concerns. Now I do my pos test and submerge it in water to look for leaks. __________________ -AJ Pirate Technical Chief Mate Director of Plundering Operations Booty Investment Analyst & Pillaging Opportunity Specialist
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