New to rebreather diving

[taimen]

ps: the inline shutoff disables the ADV, the dil MAV on the ADV, and the redundant secondary dil MAV.

The inline shutoff on JJ disables only the ADV (and possibility to manually add dil by pressing the ADV button). The dil MAV remains functional and is needed for adding diluent to the loop when inline is closed. If the inline shutoff is completely removed, the dil mav becomes redundant.

I couldn’t imagine not having a dil mav and having to rely on an adv.

Adding manually by pressing ADV is easy on JJ. Unless it is disabled with a shut-off valve.
No real need for a separate diluent MAV.
Having both MAVs also gives an opportunity to connect two offboard gases at the same time.
Very much a personal preference. Many good instructors recommend dil MAV for the international edition and likewise many recommend removing it from CE units for cleaner configuration and simpler diving.
The OP should configure according to his instructors recommendation at this point.

 

[Valyngar]

I’m ordering a JJ as my first rebreather and will do the training in September or October. Do you guys have any advice on ordering the unit like options/adjustments? I haven’t done any rebreather diving so any advice on rebreather diving is welcome. Thanks in advance.

Get normal hud and petrel2. I would recommend getting harness as DIR harness, much better than standard one. Axial scrubber is way to go at start, you can upgrade later to radial can and scrubber.

I would ask them is it possible to get plastic moulded flywheels for 1st stage regulators (much better for hands). Or change flywheel yourself.

 

[divingx]

Get normal hud and petrel2. I would recommend getting harness as DIR harness, much better than standard one. Axial scrubber is way to go at start, you can upgrade later to radial can and scrubber.

I would ask them is it possible to get plastic moulded flywheels for 1st stage regulators (much better for hands). Or change flywheel yourself.

Can I use my standard backplate for OC on JJ?

 

[tbone1004]

Can I use my standard backplate for OC on JJ?

yes

 

[taimen]

Can I use my standard backplate for OC on JJ?

Yes. I switched my (Halcyon ss) backplate and harness directly from my doubles.

 

[kensuf]

Axial scrubber is fine. I know guys that have done ridiculously long dives on the stock axial. I'm not even sure a brand new JJ diver is allowed to buy the radial scrubber.

Don't monkey with an inline shutoff (a stock JJ doesn't need it, and it could actually cause problems).

You don't need anything else on the JJ.

 

[kensuf]

have to unblock the ADV to add dil, so personal preference I guess on that.

@QAQTAT I'd have one spare sensor for class, and then you'll want the o-rings to keep as a just in case

The ADV on the JJ is pretty solid and misfiring is rare. I'd really be more concerned about having the slider off and needing to get gas into the loop but with no real method to do so. The guys I know that dive JJ's do not use them, the guys I know that dive JJ's have done some incredibly impressive dives on their units too.

 

[tbone1004]

The ADV on the JJ is pretty solid and misfiring is rare. I'd really be more concerned about having the slider off and needing to get gas into the loop but with no real method to do so. The guys I know that dive JJ's do not use them, the guys I know that dive JJ's have done some incredibly impressive dives on their units too.

agreed, that's why I said the dil MAV and ADV shutoff should be used together. No way would I ever shut off an ADV if I didn't have a dil MAV.

 

[Madddogggy]

The international version comes comes one way from the factory (default, picked mine up in January 2020).
-Axial Scrubber/5.5lbs
-Cannister/5.5lbs
-MAVs on both Dil/O2.
-Inline shutoff on ADV
-Steel backplate
-Wing
-CL
-Shearwater Petrel-II (JJ-Logo)
-Shearwater HUD
-DSV/Loop
-Batteries
- If I can remember, it came with a extra pair of filters
-anything else is an add-on to the default setup (extra cost), example can not exchange Standard canister for XRC Kit - Extended (disclaimer - unless something has change, or may be you know the right person).

-Order with the following:
Compare 3L bottle costs, I bought mine through JJ because they were less than I could get elsewhere.
JJ Sensor Cover - This is a huge help to protect the sensors and head while in storage and traveling.
Scrubber Filters: Haven't tried it yet, but I have been told the coffee filters can replace the scrubber filters.

If you change out the steel plate for an aluminum/carbon fiber, make sure the replacement backplate allows for the counter lungs to expand. I just made the change using an old scubapro aluminum backplate that had an appropriate bend angle.

 

[Valyngar]

The ADV on the JJ is pretty solid and misfiring is rare. I'd really be more concerned about having the slider off and needing to get gas into the loop but with no real method to do so. The guys I know that dive JJ's do not use them, the guys I know that dive JJ's have done some incredibly impressive dives on their units too.

I didn't know anyone that has shutoff valve still installed. It was told to me that it mostly just CE mandatory thing. It is just in too high and hard to reach. Much easier to just close diluent valve if you need to get ADV off.