Source For Replacement Sensors in the US and Elsewhere

[zider]

My calibration gas arrived yesterday so I replaced the CO sensor this morning. The calibration went smoothly with no issues. A quick breath bump test after calibration read 2.5ppm. I’d say anyone thinking about replacing the sensors themselves should give the folks at McNeil Int. a call.

 

[RayfromTX]

I changed both sensors today.

The O2 sensor is slightly bigger that the original but after removing the oring it fit in the space allowed. As previously noted the output range is one volt lower at both ends than the spec on the original and this showed up as I calibrated. The original read 12.5 volts exposed to air and the new alternate from DDScientific reads 11.5 volts exposed to air. The calibration went fine and when later testing my nitrox it reads 32.3 on a tank that previously tested 32.2 so I will accept that as a win.

The CO sensor is a direct replacement so after installing it I let the unit sit for 6 hours while I did other things before attempting to calibrate it. The instructions say to wait at least 4 hours. I used a piece of tubing for an medical oxygen canule that I had laying around. It fit over the valve outlet and gave me a soft vinyl end piece to push up against the bare CooTwo inlet. I moderated the flow by what seemed about right and let it flow for over 10 seconds before starting the calibration. After calibrating I blew a 3ppm bump test. It went to 0 when I tested my tank of 32% nitrox which had previously tested at 0 so I take that as another win.

Based on my conversation with Tiffany I will lie to the cootwo in two years and tell it I installed a new CO sensor so I can get 3 years out of this one. I believe they are overly conservative in their recommended replacement interval and I believe that when I sent it in for replacement a year ago that they failed to do so and simply calibrated it. I later asked for a refund of the sensor cost and iirc they processed the credit. The sensor I took out said 06 16 which is probably a manufacture date and it has worked up until now. That's my call. Y'all make your own call on replacement intervals. I would calibrate on a somewhat regular basis after the first year.

For me, I'm comfortable that I am back in business and have an inexpensive source for sensors and enough calibration gas to last for the many years I hope to continue diving. If I find anything amiss going forward I will come back and edit and repost any additional information that comes to light. Feel free to ask questions if I seem to have left anything out.

 

[guruboy]

Replacement CO sensor did not have a manufacture date and year on it.

My old one has it printed on the label.

 

[JohnN]

I took an old valve and nozzle from a propane torch and found a section of radiator hose with a nice bell opening that neatly fits over the CooTwo "nose". Some electrical tape around the metal shaft of the torch and my 'ghetto-special' was complete

 

[tmassey]

@RayfromTX A cheap way to sort out the regulator now that I think about it is with a cheap medical O2 regulator.

CGA600 adapter to NPT
https://www.amazon.com/MENSI-Propan...keywords=cga600+adapter&qid=1579694834&sr=8-2
Cheap regulator, remove the existing CGA fitting and it should be 1/4NPT on the inlet
https://www.amazon.com/Medline-Valu...s=medical+o2+regulator&qid=1579694853&sr=8-12

Or this one: Calibration Gas Control Valve CV-2 For 17&34 Liter Steel Cylinders CGA 600 Connection Type CalGas seems to have good pricing on bump gas as well.

This one is a lot closer to the propane torch @JohnN described than @tbone1004 ’s fancy repurposed O2 regulator, but for this job I’ll take the simplicity...

I’ve had a ToxiRAE 3 bugging me about a bump test for a while. You guys have inspired me. I’m ordering my bump gas and “regulator” (ok, valve).

ETA: I think the combo of that valve on Amazon plus the Grainger pickup of the 50ppm gas (what my analyzer suggests) is the best value. If there’s a problem with the valve like @rhwestfall mentions, Amazon returns are easier — love the magic drop boxes.

 

[rhwestfall]

Interesting enough I got one of those. QA/QC apparently had the day off when mine went out as the thing was never bored. No gas would come out of it... I drilled it myself, bit think I needed to be even smaller on the port. I'll probably get another as I have to make a new bump gas purchase...

CalGas pricing isn't too bad, but HAZMAT shipping charges.....

 

[zider]

Interesting enough I got one of those. QA/QC apparently had the day off when mine went out as the thing was never bored. No gas would come out of it... I drilled it myself, bit think I needed to be even smaller on the port. I'll probably get another as I have to make a new bump gas purchase...

CalGas pricing isn't too bad, but HAZMAT shipping charges.....

If you have a Grainger Supply store close by, you can purchase it online and pick up for free in the store. Here's a link to the 15ppm gas I ordered from them. It took a couple weeks to arrive as they probably do not keep them in stock.

https://e.grainger.com/pub/cc?_ri_=...tr1TnCCGgYxouKGHKcnkIx7pCcPtJOoaV1J1GRHiVnyfM.

 

[tmassey]

ETA: I think the combo of that valve on Amazon plus the Grainger pickup of the 50ppm gas (what my analyzer suggests) is the best value. If there’s a problem with the valve like @rhwestfall mentions, Amazon returns are easier — love the magic drop boxes.

My calibration gas just arrived at Grainger -- right before Michigan enters Coronavirus lockdown! Nice!

So, here's what I've got: a CV-2 valve from Amazon, ($20 with free shipping), a cheap acrylic 1000ml/min flowmeter from eBay, ($9.01 with free shipping), and a 17L cylinder of 50ppm CO calibration gas from Grainger, (on sale for $26.97 after tax, free pick up in store). I already had the tubing in inventory, so my total cost was $55.98.

I used 1/8" ID plastic tubing from the CV-2 valve, then used short lengths of 1/4" ID to adapt to the flow meter. I simply ziptied the flow meter to the side of the cylinder. I then used a short length of 1/4" ID tubing to adapt back to 1/8" ID tubing, and finally connected to the calibration cap for the ToxiRAE 3. Not beautiful, but effective. Started the flow and adjusted to the correct volume, and it measured my 50ppm gas as 49ppm. Nice! Walked through the calibration process to reset the countdown timer. Took maybe 10 minutes to get everything set up, and 5 minutes to complete the calibration. Re-verified the monitor using the test gas and got the right numbers!

So for less than $60, I now have a fully tested and calibrated CO monitor integrated into my compressor for continuous gas monitoring! I paid $200 in 2017 for the monitor (it's $260 now from PKSafety). Given the multiple thousands of dollars that went into the compressor in the first place, a few extra percent to monitor every cubic inch of gas I compress for the most deadly issue is really pretty nice. If you've got your own compressor, think about adding this to your setup. I've always appreciated the convenience of my own compressor, but now I'm enjoying the extra safety, too. (But don't be fooled: it's definitely not *cheaper*... ) Plus all my fills are Nitrox, which are tricky to get around here.

Hey, if you're in the Detroit, Michigan area and need fills (or VIP's, or hydros, or...), get in touch: my prices are competitive -- and my fills are verified safe!

 

[kelemvor]

I placed an order with Tiffany today. The prices have gone up slightly, in case you want to update that first post. Both sensors now cost $35usd each and shipping to Largo, FL (near Tampa) was $16.95

She also has CO. I got a 10 liter bottle of 30ppm for $44usd from her.

 

[Pedro Burrito]

I live in Suisse and I placed the order directly with DD-Scientific. They will sell single sensors. The cost was 18€ for the CO and 35€ for the O2. Shipping was high because no one wants to ship anything to Suisse. Amazon.co won't even ship to Suisse. Now I have to find the CO bump gas.

@RayfromTX , Thank you for doing the research and posting the part numbers.