O2 Sensors

[Mark Y]

The Inspiration service manual states that Teledyne O2 sensors (model R22-BUD-2) be used. Has anyone used Teledyne's R22D instead?

From what I've read (Diver Mole & Oxycheq websites), the R22D has a longer life (although the R22BUD-2's under go extra rigorous cyclic testing to ensure they can cycle repeatedly between low and high PPO2's). I guess I can see the pros & cons . . .

[Inspirationdiver]

I've used the R22D sensors in my rig. No problems with them at all. I even tried using R22D's and R22-BUD's at the same time to see if there would be a significant difference in their readings. Again, no problems. The real pro vs con here is the price, the one's from Oxycheq are a whole lot cheaper.

But keep in mind that if you have to send your electronics back to APD for any reason (upgrades, warranty, etc) they will replace all the cells with the ones they supply and charge you for them. :o

[DiverMole]

Virtually no difference between them whatsoever. performance is almost identical. The R22d's Temp sensor used to be in a slightly different place but I think even thats changed now. The only difference is that the BUDS have extra tests specified by APD the Oxycheque do

A large percentage of inspiration divers used R22D's with no problems at all

As for APD charging for cells, just a reminder that under UK law its illegal for APD to charge for goods that have not been asked for or authorised. APD have in the past had there hands slapped for this practice by Trading Standards. Of course this doesn't apply to SDI though

[Mark Y]

I found this for sale from OxyCheq:

"Sensor Saver: Machined from Aluminum, it will  fit on any threaded sensor. It attaches to your sensor when it is not in use.  It seals against the o-ring on the sensor and helps extend sensor life because it cuts off any exposure to oxygen.  It also protects the sensor membrane from any accidental physical damage. This will pay for itself.  It fits the R17 series, R22 series and R33 series sensors and any other competitor's sensors that have threads."

Will it really extend sensor life? I remember a post awhile back (could seem to find it) about cells 'going to sleep' if stored in a tight bag.  The protection aspect is somewhat moot (for me) as they are stored in the Inspiration head and 'safe' from damage.  Any comments?

[Inspirationdiver]

Hey Mark,

From what I have read about this, it's still highly debated.  In theory, by preventing o2 exposure to the cells, you should be able to extend the life of the cell.  However, many argue that it doesn't actually make any difference in the long run.  A cell (model R22-BUD-2) should last about a year in 21% o2.  Those that have tried the sensor savers claim that their cells still only last about a year. 

The other side of this arguement relates to your comment about the cells "sleeping".  When you reexpose the cell to o2, it takes a while for the reaction to start again.  So you can't simply remove the caps, calibrate, and go diving.  Some even argue that the stopping and starting of the reaction itself can reduce the lifespan of the cell. 

So if preventing exposure to o2 can extend its life, and starting and stopping the cells shortens it, maybe that's why they seem to have no effect on the cell life overall???

In my mind, I wouldn't use them simply because I don't want to be guessing if my cells are awake enough to calibrate and go diving....

[Mark Y]

How long does it take for a cell to 'wake-up'?  Say, from the shipping packaging, to rebreather, to dive...

[Deep Thought]

I have found that 24 hours is necessary for a wake up, prior to this the cells ready higher than they should. This was also told to me by Gordon of
Jetsam Technology.  Do not use the cap, the cell will last 12 months with or without the cap.  I have teledyne info on file regarind people who used to seal cells in inert gas and the same wake up proceedure occurs...I sell the cap from oxycheq and happy to provide if requested, but not recommended.

Understanding the how to calibrate, what information you are telling the computer, or what information a display is reading on a ccr is all experience knowledge and life support. 

In the past three years I have seen a decline in quality of cells,  I can't fully explain.. but cells that used to last 12-18 months are now lasting 8-12 months??  Overall they really are expendable and cheap compared to the quality of the dive, you just have to get the unit to cooperate when you want to go diving.  If you get flaky cells you have to have spares.

dt

[rcojr]

Does anyone know what the date codes on Teledyne oxygen sensors mean? I had a cell problem this last weekend. I installed a new cell straight out of the pack and let it soak for about 20 hrs. in pure oxygen.
Next dive it calibrated and worked fine untill I got to the wreck and hit it up to the high setpoint. The other cells where reading 1.3 and the new one would only get to 1.0.
DT said a cell that was waking up would read high, this was reading low. I assume that the cell was old and out of date. The date code is C2 on an R-22D cell.
Bob

[Inspirationdiver]

Hey Bob,

The letter indicates the month, and the number is the year.  So C2 would be March 2002.  That's a pretty old cell...

[rcojr]

Zach
Thanks
That is what I thought ,but wasn't sure.
Bob