Oxygen System Overhaul

[Z W]

After chasing oxygen system leaks for years in our M20K, we've decided the factory O2 system from 1982 needs an overhaul.  Currently it has a very slow leak where if we fill the tank, it will leak down over a period of about three weeks.  Usually just long enough to be empty before the next flight that oxygen is needed.  After living with it for over a year, we've had enough.

Also, ever since we got the plane, if you leave the valve in the "On" position after flight, the tank will be empty by the next morning.  My understanding is this is from leaks most likely at the female Scott type fittings in the side panel in the cockpit, which are prone to leaking as they age.

Anybody been down this road before?  Thinking about telling the A&P to replace everything accessible from the tailcone, and if that does not fix the slow leak, then the lines from the tailcone to the cockpit and all those fittings are getting replaced.  I believe if it's functioning properly you can leave the oxygen "On" all the time (or at least overnight) and not have it be empty the next day.  May well have them replaced anyways.

Any reason to install the Precise Flight oxygen system in a Mooney that has factory O2?  It seems to be the only STC'd option:

https://preciseflight.com/product/built-in-oxygen-system-for-mooney/

All I see is additional complexity and electrical components that will basically do what the factory gauge and manual valve already do.  But I'm open to ideas.

May also add a Mountain High O2D2 system while we're at it.  Has anybody mounted one of these on the ceiling?  If so, I would like a photo.  Searches turned up pictures of some mounted on the center console above the fuel selector, but it seems like it would be in the way there, and it doesn't look like a super clean install.

Any experience or guidance would be appreciated.  Thanks.

[N201MKTurbo]

It seems to me like fixing your current system would be cheaper and easier than replacing the whole thing. Besides, what makes you think the new one will leak less than the current one? Either way you go, it is still a big collection of tubes and fittings that some mechanic has to assemble.

[A64Pilot]

Obviously be darn sure no kind of petroleum gets anywhere near any fittings etc. I’m so paranoid I’d only use O2 leak detection fluid as I’ve heard that some soaps may even have a little oil in them. Probably not, but why chance it?

I even clean off any tool I use with alcohol first.

[GeeBee]

Might want to talk to the "Oxygen Lady" (Phoebe) over at KRHV. She seems to know a lot.

 

https://www.aviationoxygen.com

[carusoam]

Around MS…

When it comes to O2 systems… We have seen anything that can leak… will leak.

The most unique leak… was a sheet metal screw that penetrated one of the copper tubes delivering O2 to the cockpit…

The most easy leak… mixing ferrules from one supplier with a different supplier…

 

A leak detector liquid is called ‘snoop’….  Search for snoop… find all the prior MS experience…

https://mooneyspace.com/search/?q=Snoop&quick=1

Best regards,

-a-

[xavierde]

I've had a great experience with TurboProp East (at KAQW) but it was limited to swapping and testing the regulators on the O2 bottle.

Someone also recommended C&L aero but it's on the West coast.

[Z W]

Thanks for the tip on Snoop.  Have a bottle ordered.  Thanks for the other tips as well.  

[Guest]

For the slow leaks from the cylinder when the system is off, remove the cylinder from the plane, fill it to 1800 psi and put it head first in a pail of clean water and watch for bubbles.  Many times it’s the thread between the regulator and the cylinder, composite cylinders use a special metal washer and torque, metal cylinders use a tapered pipe thread and Teflon tape.  Other sources of leaks are pressure gauge fitting on the regulator and the fill line fittings.

Clarence

[Z W]

A&P found a leak in the filler valve.  Mooney part number 26875-76.  Apparently it's hard to find.  Working on a source.  Looks like this:

download.jfif

Edited September 16, 2021 by Zane Williams

[N201MKTurbo]

31 minutes ago, Zane Williams said:

A&P found a leak in the filler valve.  Mooney part number 26875-76.  Apparently it's hard to find.  Working on a source.  Looks like this:

download.jfif 5.08 kB · 1 download

That is a Scott-Zodiac fill valve.

[Schllc]

two thumbs up for precise flight system.  i suppose any on demand system will be better than factory, but i will install the precise flight on anything that i own.

[hubcap]

I can certainly recommend the Mountain High O2D2 system. When using the O2D2 system it makes your oxygen last what seems like forever. Before getting the O2D2 system with my wife and I both on O2 we would use almost an entire tank on a 4 hour flight. Now the gauge barely moves on a 4 hour flight.

[Z W]

We have oxymiser-style cannulas and that helps.  With two in the plane I would say we get 10-15 hours of flight on oxygen per bottle.  I like the idea of the O2D2 though, because if it could be 20+, why not?  At $80 per fill at home base it seems to make a lot of sense and would pay for itself in a few years.  My only concern is clutter in the cockpit. 

Did you semi-permanently mount your O2D2, or is it just plugged in?  Where did you run the lines?

[kortopates]

A&P found a leak in the filler valve.  Mooney part number 26875-76.  Apparently it's hard to find.  Working on a source.  Looks like this:
download.jfif

Very common. send the fill portal to C&L Aero and he’ll install a new high pressure needle valve - easily repaired and not expensive.


Sent from my iPhone using Tapatalk

[Z W]

Thank you for the tip on C&L Aero.  We'll give them a call!