Water ingress & recovery in KISS Classics

Goferrin

New Member
I can hear the purists cringing in horror but has anyone done anything to enhance a KISS Classic's water control or flood recovery abilities?

Like most rebreathers I return from 1 to 2 hour dives with some water in the system and the only way I have to expel this is to try to pour it out of the scrubber. Some exits through the central tube but most simply washes up through the sorb when the canister is tilted. After two or three dives the water is definitely noticeable while diving.

It would be great to exhaust any water present while diving or at least between dives.

Past posts have had little info on options and have just degenerated in agreements with little true information.

Options I can see are:

Do nothing and continue as is.

Add a chamois type absorbent to hold any water in the system and dry between dives.

Add a LP blanking plug to the base plate of the scrubber to allow water to be drained between dives with out compromising the sorb.

Add a Vent/OPV to the base plate to allow venting water mid dive.

Has anyone tried any of these or have any comments/suggestions?
 
Some one on the kiss rebreathers Facebook group was selling a new base with a dump valve in it.

Alternatively I have thought of moving the inhale/ exhale hoses from the top of the head into the top of the lungs so the gas flow is directly through the lungs and they can catch any water. The original turrets would need blanking iff
 
I've never had much water in the base of my unit even after long dives
where the scrubber is going to be changed it's still pretty dry.
If I had to drain it I would use a larger syringe with some tube on the
end and suck it up through the down tube.
 
Mike, I don't know if you saw it, but I had one of those big far syringes as well which seemed to work ok.


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1) I add a shamois at the bottom of the canister. Same kind as the one used in Megs.
2) Between dives I remove the base of the canister to dry out the shamois and remove the water.

The trick to do it is to generously apply silicone grease to the o-rings of the base plate and to the bottom part (inside) of the tube. 1) Remove the complete scrubber keeping the rig upright. 2) Hold the tube and push the central rod down. The top and bottom plates will stay in place and the sorb won't be disturbed.
 
Do people generally get much water in the bottom of the scrubber ?
I guess it's not a leak but condensation ?
I can't figure out how I get so little, apart from the once I forgot
to close the BOV, I got a lot then :xeye:
 
I never get much. For instance, I'm just back from a week in Egypt and I got about 10 cc after 6 hours scubber time (2 or 3 dives a day). Half of that in the exhale CL. The rest in the shamois. It was wet but not damp. That's a mix of drool and condensation.
 
Thanks guys. All good suggestions but honestly simple drain screw would be so easy to install and use

I would get about 1/2 a cup or less per dive split between the lungs and base plate. Like the other posts i have had a lot more but that was due to loose lips or leaking mouthpieces or BOVs
 
If I regularly got enough water in the base of my KISS to cause me to want to put a drain screw in, I'd be asking why?

Yes I got a dribble of water in the unit but realy nothing worth worrying about

Id be more concerned about water getting in via my new drain plug :D

I designed this for my KISS about 10 years ago but never got arround to building it.

I might do it for my new KISS

KISSwatertrap2.jpg
 
If I regularly got enough water in the base of my KISS to cause me to want to put a drain screw in, I'd be asking why?

Yes I got a dribble of water in the unit but realy nothing worth worrying about

Id be more concerned about water getting in via my new drain plug :D

I designed this for my KISS about 10 years ago but never got arround to building it.

I might do it for my new KISS

KISSwatertrap2.jpg

Then again if it isn't broke why fix it ?

I get so little water in my unit I don't have a problem.
I would like some sort of flood recovery though, just
in case I ever had enough water in that caused me to
have to bail out.
I seen a guy selling scrubber bases with dump valves
fitted but what would happen if you were inverted ?
 
I see a functional dump valve as the best solution to both scenarios - major ingress during a dive that needs to be expelled or minor moisture that would be beneficial to remove between dives.

That said, the devil would be in the details as a manually or over pressure operated dump would be sitting in a very caustic environment possible with the odd sorb pellet just waiting to degrade or unseat valves

I'm leaning towards a full flood mid dive leads to a bail out but minor moisture is removed via a drain. It would be relatively easy to seat a threaded drain screw and have it seal properly while diving as there is minimal pressure difference between inside and outside of the scrubber.
 
Then again if it isn't broke why fix it ?

I get so little water in my unit I don't have a problem.
I would like some sort of flood recovery though, just
in case I ever had enough water in that caused me to
have to bail out.
I seen a guy selling scrubber bases with dump valves
fitted but what would happen if you were inverted ?


Which is why I didnt get arround to doing it.

On the other hand, the unit has very low flood tolerance and no way of managing it, so if I did have a 1ltr water trap in the bottom of the scrubber? It could be usefull


My concept was, go vertical and water drains into water trap then go horizontal and the baffell stops it entering the scrubber material

I did consider an OPV type water dump so I could presurise the loop and blast water out of the bottom in a vertical position but I was / am concerned this would become the primary water ingress point :(

A drain plug would be plan B

Inverted would be an issue but then what hapens with the OPV on the top of the KISS?

ATB
 
Last edited:
Inverted would be an issue but then what hapens with the OPV on the top of the KISS?

ATB

The way I see it is the dump valve at the bottom would have to be set to open
at a lower pressure than the top one, or it would just stay closed and the gas
would escape from the top one leaving the water in the base.
Then if it's set to open at low pressure you loose gas when inverted, i.e. taking
spidge out of a hole.
Another way would be with a pull dump fitted to the base with a strong spring
to keep it closed (like on a lift bag) but then you have the routing of the toggle
to deal with to prevent it getting opened by accident.
It's a bit of a head scratcher ;)
 
Then going back to where is water getting in could be the answer. I found less issues with loose lips when I moved to a Drager mouthpiece with with strap. Going to be diving mine in colder water now, so maybe shorter dive time, but more chance of condensation.


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Then going back to where is water getting in could be the answer. I found less issues with loose lips when I moved to a Drager mouthpiece with with strap. Going to be diving mine in colder water now, so maybe shorter dive time, but more chance of condensation.


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Could be why I have so little in my unit, I've used the Drager from I got the unit.
 
I tend to drool a lot. Every hour or so I get the hose gurgles and go vertical and let it run into the scrubber/ lung. After a few hours of this there is always quite a bit in the scrubber
 
Dave, which BOV do you have it fitted to?

Does it fit on the DiveRite (same size mouthpiece as a Apeks reg)?

I understand the mouthpiece cannot be changed to a different size as its integral to the gag plate, correct?

I just got back from a decent scooter run in strong current with minimal water in the base plate. No loose lips from consciously having to clamp down on the mouthpiece and lip seal made all the difference. I'm keen to attack both fronts - minimise ingress AND be able to remove what ever is there between dives
 
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