Transforming eCCR into hCCR

[LFMarm]

How difficult is it to convert a eCCR unit into a hCCR (if at all possible)? If you do it, what are the drawbacks?

Context: I am landing on an OptimaCM because of its flexibility and ease of travel. This is a eCCR but I think that the idea od hCCR is great as it minimizes the solenoid use while still being able to run in auto.

 

[kensuf]

The main way people convert an eCCR to an hybrid is to replace the O2 MAV with one that either has an orifice or needle valve. Sub-Gravity is offering this option for their Defender and X-CCR.

Unfortunately, I don't think it'll be particularly easy to do with the OptimaCM. The reason is because the MAV is a drysuit inflator attached directly to the exhale counterlung. It may be theoretically possible to replace the inflator with a blanking plug with a port to plumb a needle valve, but it would probably be a lot more hassle than it's worth, especially if this is going to be your first unit.

 

[Tracy]

How difficult is it to convert a eCCR unit into a hCCR (if at all possible)? If you do it, what are the drawbacks?

Context: I am landing on an OptimaCM because of its flexibility and ease of travel. This is a eCCR but I think that the idea od hCCR is great as it minimizes the solenoid use while still being able to run in auto.

It is doable, as ken said, you would have to modify the MAV and plumb in there unless you wanted to add a t-piece somewhere in line.
My big question is WHY?
What are you trying to accomplish?

 

[LFMarm]

My big question is WHY?
What are you trying to accomplish?

Conceptually it makes a lot of sense to add the metabolic oxygen consumption and use the solenoid only for hard work efforts and ascent. I am just trying to learn more on the topic so I have not decided if that is the way to go.

 

[sea_ledford]

If you are on Maui, you need to go talk story with Todd and Tiffany Winn. They run Silent O Solutions, but it's easier to find them at Whalers Locker in Lahaina.

 

[tbone1004]

How difficult is it to convert a eCCR unit into a hCCR (if at all possible)? If you do it, what are the drawbacks?

Context: I am landing on an OptimaCM because of its flexibility and ease of travel. This is a eCCR but I think that the idea od hCCR is great as it minimizes the solenoid use while still being able to run in auto.

In order:
Difficulty-on most units it is incredible easy. As said above it is usually as easy as replacing the O2 MAV with a MAV containing a CMF or Needle valve. With the CMF you have to plug the O2 regulator for fixed IP, and with the needle valve you can choose to plug or not to plug.
Drawbacks are the CMF's create a depth limit for the CCR since you remove the depth compensating capability of the first stage, have the potential to get clogged, and are somewhat annoying to get the flow rates correct especially if you dive in varied conditions. Needle valves need to be adjusted *more often if you do not fix the IP on the first stage, less often if you do*, and if you fix the IP of the first stage have the same depth limitations as the CMF's.

I am certified on both eCCR and mCCR, and I do not use a leaky valve MAV on my eCCR's. The reality is on both units you are having to add O2 manually and while the leaky valve certainly increases the time between additions, it's not really worth the added complexity and hassle of dealing with the leaky valve. I run my eCCR in parachute mode with the setpoint at 0.7 and run the unit around 1.0-1.1 and it is several minutes between O2 additions. Changing 2-3 minutes to 10 minutes is not really something that warrants the added cost/complexity in my opinion.

Speaking strictly to the Choptima, it is certainly not practical to change that unit to hCCR and would also make it a bit unwieldy to have the block around.

 

[LFMarm]

Thanks all — all plans for the hCCR conversions are now scrapped

 

[missionmtb]

I converted mine to hCCR and I love it (similar unit). Assuming its the same solenoid, just swap the stem in your jaksa solenoid with the Revo one and use a blocked first stage Can always switch it back by putting the old reg on and a port plug in the end of the stem (say if you're doing a deepish tech dive). Conversion will cost you maybe $3-400. Having the extra time between O2 squirts really makes the MAV-work less obtrusive during dives, especially shallow ones with lots of depth changes. Only difference I notice in this configuration is the PO2 is more stable at a given depth and buoyancy is more manageable because you're not messing it up by holding the MAV too long or whatever.

-m

 

[Dsix36]

I have messed with about every configuration there is and even made a couple of units myself. imho, the quickest, easiest, and overall best means of conversion is to merely swap the mav with a mav that contains a needle valve. do not blank the first stage and do not fiddle with the needle valve very much. I have found that all i ever did was to do one thumb twist on the needle valve to do what was needed. I have seen CL mounted valves with the needle valve built into them also and for the optima, that would be my choice

 

[Teleopsis]

So from what I read here it sounds as though i could convert my JJ into an hCCR by replacing the O2 MAV with one with a needle valve. Is that right? Would I need to mess with the first stage?
Not planning to do this, just wondering...