The JJ-CCR Counter Lungs walk through

It all started from a little hiss that seems to be coming from nowhere…
My unit failed the negative check after only two or three minutes, I checked all the connections, the O-rings but to no avail… I blamed my new BOV, my old regulators but nothing helped, the unit failed time after time.

I was doomed to face the worst… looking inside the counter lungs!
It seems like the hardest part to maintain are the counter lungs, but in hindsight after doing the whole process of disassembling and reassembling the whole thing, it wasn’t that bad.

(To make a long story short, yes I had a puncture in my inhalation CL).

The counter lungs are made of 8 primary components:
Counter lung cover
Two counter lungs
Two T-Pieces
Two flanges
Dump valve

The T-pieces are connected to the CL using a delrin flange by three 15mm 2.5 Alen key screws.
By removing the screws, the T-Piece can be pulled out by holding the base of flange and prey the T-Piece out.
Applying a pressure on the base of the flange is very important, otherwise by pulling the fabric it is easy to damage the CL.

After the T-pieces were removed the CL looks like this:

Pay attention to the O-ring of each t-piece, it accumulates a lot of debris and should be examined, cleaned and lubricated.

There are two slots on the t-piece, the lower one is narrower and should accommodate the O-ring. The upper one is made for the Allen screws and allows it to swivel.

Removing the CL requires a special tool, there is no way to do it without, and you will damage the CL by trying to do so.
The tool is a pin spanner wrench and the right size is 80-90.

The right way to open the flange is to apply a friction to the inner part using two fingers while twisting the outer part to the left, the pin of the spanner should fit perfectly inside the holes of the Allen screws.

After several tries the flange will give up and will start to spin, don’t be tempted to do the rest of the job without the spanner, use it until completely open.

After the flange is open you can remove the CL from the cover and examine it for holes or tears.

The flange (from left to right: inner part, gasket and outer part)

Repairing the CL is very easy, all is needed is the TearAid type A

Just follow the manufacturer’s direction, it works great and the material is very close to the material the CL is made from!

Assembling the CL is pretty much the same but backwards, the only tip I have is to begin by inserting the inner part and the gasket inside the CL, then put it inside the cover and then using both hands twist both parts together for a thread or two and then continue by applying a friction to the inner part and twisting the pin spanner to the right.

This is how i apply friction to the inner part.

In order to seal the outer part against the gasket you should apply some pressure using the spanner but not too much so it will be possible to open it again in the future.

 

Published by

Udi

As an engineer, i find rebreathers and technical diving a fascinating hobby. I am a GUE Rebreather diver, using the JJ-CCR and always looking for ways to improve it's performance and usability.