COUCH DIVE!
Did "X-Men Final" on the thing, plus about 10-15 minutes on the stationary bike. Couldn't overbreathe the scrubber (running as an oxygen rebreather, as the controller is not in the head - all manual add) but it got QUITE uncomfortably hot on the inhale size gas-wise (no cooling on the intake side since the hoses and can aren't immersed in water.)
I set it up with a full load of 'sorb (~7lbs) and was running Spherasorb (what I had laying around); I've ordered up some 4-8 Sodasorb and will also get some 6-12. The 4-8 has indicator as well so I should be able to figure out how that'll work out vis-a-vis the 6-12 - I doubt there will be a WOB issue with the 6-12 though from tonight's test.
Interestingly enough the indicator in the 'sorb post-use showed very little consumed in the stack - perhaps 20% - and absolutely no indication of channeling at all - there was NO violet up more than about 2" from the bottom.
I don't know how accurate the indicator is......
One thing I did learn is that the Ts need better "bypass holes" around the bottom, as it was possible to get the counterlungs into a position that restricted gas flow somewhat significantly - not enough to cut it off, but defnitely enough to notice. That's not so good. However, other than that, work-of-breathing was in the "not detectable" realm at ordinary levels of exertion, and only slightly noticable on the bike. This is with the McMaster-Carr polyethylene "filter cloth" at the top of the scrubber to prevent any dust that otherwise might be in the pack from coming through, so that's definitely going to be in there full-time - it has no negative discernable impact on the unit's WOB.
No problems detected (other than the obvious - you have to hit the O2 add every couple of minutes or you find yourself unable to breathe as the bag gets depleted of gas!)
My only gripe? Couldn't take a drink or eat any popcorn with the DSV in my mouth. On the other hand this is the first time I've breathed off ANY dive gear for 2 hours straight without a hint of cottonmouth or a NEED to remove the mouthpiece and get some water. Now THAT was a pleasant change....
My kid took the picture - she thought I was awful goofy-looking on the couch....
Looks like a decent profile too - doesn't stick out beyond the profile of my body on the couch at all. I like it. I may not like the counterlungs - we'll see how they are in the water, but I suspect I'll be making some custom ones out of something (perhaps compressed neoprene) shortly.
Potting compound should be here midweek and then the 'leccies are going in the head..... at that point it will be time for some "automated" couch runs followed by Mr. Pool....