Neg test using an empty scrubber

Paul Brookes · 21st August 2006, 16:22

Hi

Do any of you have any suggestions on how I can perform a negative pressure test on my unit without having to fill the scrubber?

After I strip, clean and reassemble the unit, I want to check everything is sealing correctly and not wait until I am water side wihout time to remediate any issues.
I know I can theoretically fill the scrubber and leave it sealed indefinitely, but I prefer to fill the scrubber immediately before the dive.

Are there any tricks that you use to "pad out" the scrubber cannister so the o-rings seal correctly?

Thanks
Paul

***Beanie*** · 21st August 2006, 16:27

You don't need a scruber to pos and neg test.

The scruber won't affect the gas tightness of the loop, the only thing you can't do without the scruber (apart from dive) is a calibration

Paul Brookes · 21st August 2006, 16:41

I was thinking in terms of the empty cannister not holding the o-ring in place correctly. What do you use instead of s/lime to make the cannister the correct size and make everything fit correctly?

Or am I missing the point of that particular o-ring?

***Beanie*** · 21st August 2006, 16:45

Quote: (Originally Posted by Paul Brookes)

I was thinking in terms of the empty cannister not holding the o-ring in place correctly. What do you use instead of s/lime to make the cannister the correct size and make everything fit correctly?

Or am I missing the point of that particular o-ring?

Yes that Oring stops the gas going round the scrubber not gas getting out of the loop.

Paul Brookes · 21st August 2006, 16:50

Ah. And who said there was no such thing as a stupid question.
That's the trouble with having no other Rebreather divers in my club.

Thanks,
Paul

decoweenie · 21st August 2006, 17:03

Quote: (Originally Posted by Paul Brookes)

That's the trouble with having no other Rebreather divers in my club.

Yes, but your instructor should have explained that part during the course...

CCR900 · 21st August 2006, 17:34

Dumb question or not ...Now you know and that's what's important

F

dive2dive2000 · 21st August 2006, 21:32

Quote: (Originally Posted by decoweenie)

Yes, but your instructor should have explained that part during the course...

Maybe he did... I know I did not absorb everything my instructor taught.

01RMB · 22nd August 2006, 06:41

Quote: (Originally Posted by Beanie)

Yes that Oring stops the gas going round the scrubber not gas getting out of the loop.

And hence the reason why you need to be so sure that the o ring is installed correctly with the spacer. Pos and neg test won't pick it up if it is not there.

I always leave the o ring and spacer in the external scrubber cannister to make sure that it is never left out when I put the breather together.

The only chance to pick up that it is not in place before a CO2 hit underwater is the pre breath. This is one reason why no matter how much of a hurry you are you should have a good pre breath and check for symptoms of CO2 and if fitted check that the temp stik starts to register.

Allan_o · 22nd August 2006, 08:11

Just qurious.

Would one be able to register a co2 build up while prebreathing the unit, without the o-ring and spacer, only by looking at the tempmeter and not your breath???

Regards Allan

21st August 2006, 16:22	#1 (permalink)
Paul Brookes New Member Current Rebreather/s: Inspiration Classic Other Rebreather/s: Join Date: Jan 2006 Location: Bournemouth, UK Posts: 35	Neg test using an empty scrubber Hi Do any of you have any suggestions on how I can perform a negative pressure test on my unit without having to fill the scrubber? After I strip, clean and reassemble the unit, I want to check everything is sealing correctly and not wait until I am water side wihout time to remediate any issues. I know I can theoretically fill the scrubber and leave it sealed indefinitely, but I prefer to fill the scrubber immediately before the dive. Are there any tricks that you use to "pad out" the scrubber cannister so the o-rings seal correctly? Thanks Paul
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21st August 2006, 16:27	#2 (permalink)
*Beanie* Gallery Administrator Current Rebreather/s: Inspiration Classic Other Rebreather/s: Inspiration Vision Join Date: Jan 2005 Location: In da house! yeah baby! Posts: 3,292	Re: Neg test using an empty scrubber You don't need a scruber to pos and neg test. The scruber won't affect the gas tightness of the loop, the only thing you can't do without the scruber (apart from dive) is a calibration __________________ Beanie Gallery Admin & Library Assistant. www.outlawdivers.org.uk www.beandiving.co.uk www.beanengineering.co.uk
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21st August 2006, 16:41	#3 (permalink)
Paul Brookes New Member Current Rebreather/s: Inspiration Classic Other Rebreather/s: Join Date: Jan 2006 Location: Bournemouth, UK Posts: 35	Re: Neg test using an empty scrubber I was thinking in terms of the empty cannister not holding the o-ring in place correctly. What do you use instead of s/lime to make the cannister the correct size and make everything fit correctly? Or am I missing the point of that particular o-ring?
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21st August 2006, 16:45	#4 (permalink)
*Beanie* Gallery Administrator Current Rebreather/s: Inspiration Classic Other Rebreather/s: Inspiration Vision Join Date: Jan 2005 Location: In da house! yeah baby! Posts: 3,292	Re: Neg test using an empty scrubber Quote: (Originally Posted by Paul Brookes) I was thinking in terms of the empty cannister not holding the o-ring in place correctly. What do you use instead of s/lime to make the cannister the correct size and make everything fit correctly? Or am I missing the point of that particular o-ring? Yes that Oring stops the gas going round the scrubber not gas getting out of the loop. __________________ Beanie Gallery Admin & Library Assistant. www.outlawdivers.org.uk www.beandiving.co.uk www.beanengineering.co.uk
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21st August 2006, 16:50	#5 (permalink)
Paul Brookes New Member Current Rebreather/s: Inspiration Classic Other Rebreather/s: Join Date: Jan 2006 Location: Bournemouth, UK Posts: 35	Re: Neg test using an empty scrubber Ah. And who said there was no such thing as a stupid question. That's the trouble with having no other Rebreather divers in my club. Thanks, Paul
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21st August 2006, 17:03	#6 (permalink)
decoweenie Crash Test Dummy Current Rebreather/s: Other CCR Other Rebreather/s: Other CCR Join Date: Feb 2005 Location: Cairo Posts: 5,487	Re: Neg test using an empty scrubber Quote: (Originally Posted by Paul Brookes) That's the trouble with having no other Rebreather divers in my club. Yes, but your instructor should have explained that part during the course... __________________ "...after a while you get bored offering advice to a bull that like to keep butting the fence with its head rather than walking through the open gate..." - Rebreather World PM
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21st August 2006, 17:34	#7 (permalink)
CCR900 Custom Title Allowed! Current Rebreather/s: Ouroboros Other Rebreather/s: Inspiration Classic Inspiration Vision Join Date: Nov 2005 Location: England Posts: 333	Re: Neg test using an empty scrubber Dumb question or not ...Now you know and that's what's important F
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21st August 2006, 21:32	#8 (permalink)
dive2dive2000 PRISM DIVER & LUVIN IT! Current Rebreather/s: Prism Topaz Other Rebreather/s: Join Date: Feb 2005 Location: Long Island, NY Posts: 795	Re: Neg test using an empty scrubber Quote: (Originally Posted by decoweenie) Yes, but your instructor should have explained that part during the course... Maybe he did... I know I did not absorb everything my instructor taught. __________________ Safe Diving, Martin
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22nd August 2006, 06:41	#9 (permalink)
01RMB Evolving Current Rebreather/s: Evolution Other Rebreather/s: Join Date: May 2005 Location: Brisbane, Australia Posts: 193	Re: Neg test using an empty scrubber Quote: (Originally Posted by Beanie) Yes that Oring stops the gas going round the scrubber not gas getting out of the loop. And hence the reason why you need to be so sure that the o ring is installed correctly with the spacer. Pos and neg test won't pick it up if it is not there. I always leave the o ring and spacer in the external scrubber cannister to make sure that it is never left out when I put the breather together. The only chance to pick up that it is not in place before a CO2 hit underwater is the pre breath. This is one reason why no matter how much of a hurry you are you should have a good pre breath and check for symptoms of CO2 and if fitted check that the temp stik starts to register. __________________ Cheers Rod
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22nd August 2006, 08:11	#10 (permalink)
Allan_o New Member Current Rebreather/s: Inspiration Classic Other Rebreather/s: Join Date: Dec 2005 Location: Copenhagen Denmark Posts: 81	Re: Neg test using an empty scrubber Just qurious. Would one be able to register a co2 build up while prebreathing the unit, without the o-ring and spacer, only by looking at the tempmeter and not your breath??? Regards Allan
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