Overhaul of built-in oxygen tank valve/regulator

[larryb]

I am pretty sure my built-in oxygen valve/regulator assembly needs to be overhauled. For those who have had theirs serviced, my question is who did the overhaul, about how much does it cost, and about how long did it take?

This is in my 1997 Encore. Since I bought it last may it has leaked oxygen out. Sometimes stopping at 700 psi, sometimes lower. I did a test where I plugged a tube into the low pressure port and put the other end in a water bottle. Even with the valve lever fully off a continuous stream of bubbles comes out the tube. I have checked the shutoff valve linkage, and the valve lever is in the full off position. So it isn't a simple adjustment. Wiggling the shutoff valve lever, I can get the stream of bubbles to stop. But there then the next use, it won't fully shutoff again and the pressure continues to drop. I have done extensive leak detection fluid testing and found nothing.  I have pretty much convinced myself that the valve is the culprit.

[kortopates]

I am pretty sure my built-in oxygen valve/regulator assembly needs to be overhauled. For those who have had theirs serviced, my question is who did the overhaul, about how much does it cost, and about how long did it take?
This is in my 1997 Encore. Since I bought it last may it has leaked oxygen out. Sometimes stopping at 700 psi, sometimes lower. I did a test where I plugged a tube into the low pressure port and put the other end in a water bottle. Even with the valve lever fully off a continuous stream of bubbles comes out the tube. I have checked the shutoff valve linkage, and the valve lever is in the full off position. So it isn't a simple adjustment. Wiggling the shutoff valve lever, I can get the stream of bubbles to stop. But there then the next use, it won't fully shutoff again and the pressure continues to drop. I have done extensive leak detection fluid testing and found nothing.  I have pretty much convinced myself that the valve is the culprit.

Call these folks, they’re a repair station specializing in O2 system. They’re also very reasonable.
https://www.c-l-aero.com/


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[DonMuncy]

Is the situation that you can go back to the regulator and shut it off by hand, but when you use the lever in the cabin, it won't shut off? The wire that comes in the plane is too small to be able to reliably shut off the flow, after a period of time. Mine did that. My hangar elf changed to the next larger size (sourced from California Push-Pull, Inc.) and it has worked fine for a long period of time. Not too much trouble and cheaper than a regulator overhaul.

[carusoam]

Larry,

There have been a few discussions matching your description...

The best part is, Don Muncy summed them up pretty well...

Expect you might have a cable separating somewhere...

PP thoughts only, I don’t have an O2 system...

Best regards,

-a-

[larryb]

36 minutes ago, DonMuncy said:

Is the situation that you can go back to the regulator and shut it off by hand, but when you use the lever in the cabin, it won't shut off? The wire that comes in the plane is too small to be able to reliably shut off the flow, after a period of time. Mine did that. My hangar elf changed to the next larger size (sourced from California Push-Pull, Inc.) and it has worked fine for a long period of time. Not too much trouble and cheaper than a regulator overhaul.

hi Don:

No, I have actually already replaced the wire. The wire was broken at the knob. The knob in the cabin is able to fully shut the valve at the tank without difficulty.

There have been two other repairs as well. The little o-ring on the high pressure fitting at the tank has been replaced. And there was a small leak, found with the leak detection fluid, at the high pressure fill port Swagelok fitting. That fitting has been replaced and no longer leaks. The system had multiple problems.

The test where the system blows bubbles out the low pressure port when the valve is fully shut is what makes me suspect the regulator/valve.

Thanks, Larry

[MIm20c]

58 minutes ago, kortopates said:

Call these folks, they’re a repair station specializing in O2 system. They’re also very reasonable.
https://www.c-l-aero.com/


Sent from my iPhone using Tapatalk

Call Jeff, he is VERY knowledgeable about everything O2 related.  Talked my ear off with a massive amount of Mooney specific info.  Reasonable, and has many positive reviews on BT. 

He will test your equipment and fix what is necessary up to a full overhaul. 

[thinwing]

Having replaced tank and had regulator re cerified...it is prob just a simple cable push pull adj....

 

[kortopates]

11 hours ago, thinwing said:

Having replaced tank and had regulator re cerified...it is prob just a simple cable push pull adj....

This is usually the problem the majority of times.

15 hours ago, larryb said:

Wiggling the shutoff valve lever, I can get the stream of bubbles to stop. But there then the next use, it won't fully shutoff again and the pressure continues to drop.

That description leaves some doubt that its rigged properly. If you were to remove the cable at the valve and then could just lightly push the valve arm to the off position without leakage then that shows its not the valve but rigging. If on the other hand lightly pushing the valve to off isn't enough to repeatedly stop the flow, then that is a valve/regulator issue. But what most people don't realize is that the cable needs to be rigged so that it pushing the valve closed under some tension in the off position, i.e. the cable has to have the ability to go a bit past the closed position to ensure it's being pushed 100% to closed. Just wanted to share that in case you might still have a cable rigging issue because it is so very common after the bottle comes out for a hydro testing that the cable isn't rigged properly enough to ensure valve shut off when it goes back in.  

[larryb]

The cable is rigged such that there is positive pressure on the lever from the cable in the fully closed position from the knob. The lever is fully closed before the knob reaches it's stop. In fact, bubbles stopped when I moved the lever slightly towards the open position from the fully closed position.

[kortopates]

4 hours ago, larryb said:

The cable is rigged such that there is positive pressure on the lever from the cable in the fully closed position from the knob. The lever is fully closed before the knob reaches it's stop. In fact, bubbles stopped when I moved the lever slightly towards the open position from the fully closed position.

You have me convinced - just wanted to make sure

[larryb]

To followup, I contacted Jeff at C&L Aero in Redding. I shipped my whole oxygen tank and valve assembly to them on Friday morning, and it was returned to me the following Thursday afternoon. 6 days total turn around time including shipping. I'm only a couple hundred miles away, so UPS ground is next-day.  I was 2 years from needing a hydro inspection, but I had that done early since it was all out and on-site. The total for the overhaul of the first stage regulator and shutoff, testing of the altitude compensating 2nd stage regulator, tank hydro, and return shipping came to $683. Jeff did confirm my diagnosis of the shutoff valve not fully shutting off. The best news, the system in the aircraft finally holds pressure. It's been several weeks now with no pressure loss.

I am very satisfied, and thank you to kortopates and MIm20c for suggesting C&L Aero.

[M20F-1968]

You and to be sure that the valve turns on and completely turns off with the cable disconnected.  The valve has a time limit when it must be rebuilt.  15 years is something I remember but you will want to check.  Aerox in Maine did mine.  They still have their offices in Maine but moved their shop to Florida.  They were easy to deal with.  Recertified the tank at the same time.

John Breda

[pwnel]

On 4/20/2018 at 5:08 PM, larryb said:

To followup, I contacted Jeff at C&L Aero in Redding. I shipped my whole oxygen tank and valve assembly to them on Friday morning, and it was returned to me the following Thursday afternoon. 6 days total turn around time including shipping. I'm only a couple hundred miles away, so UPS ground is next-day.  I was 2 years from needing a hydro inspection, but I had that done early since it was all out and on-site. The total for the overhaul of the first stage regulator and shutoff, testing of the altitude compensating 2nd stage regulator, tank hydro, and return shipping came to $683. Jeff did confirm my diagnosis of the shutoff valve not fully shutting off. The best news, the system in the aircraft finally holds pressure. It's been several weeks now with no pressure loss.

I am very satisfied, and thank you to kortopates and MIm20c for suggesting C&L Aero.

Based on your feedback here I also had a chat with Jeff yesterday.  Super helpful.  (I believe my regulator has never been looked at since installation 1985 - at least I can't find anything in the logs).  

My question as a new Mooney owner:  when you remove and ship like you did, how is the airframe logs handled?  Should there be an entry?  If I do the work to overhaul the regulator I'd prefer to have it appear in the logs.

[larryb]

If you want to fly with it removed you can log it and update the w&b. I did that and then let my shop handle the install sign off. You will get paperwork back from c&l that you can attach to the logs. After reinstall you can remove the temporary w&b form from the poh.

 

[kortopates]

48 minutes ago, pwnel said:

Based on your feedback here I also had a chat with Jeff yesterday.  Super helpful.  (I believe my regulator has never been looked at since installation 1985 - at least I can't find anything in the logs).  

My question as a new Mooney owner:  when you remove and ship like you did, how is the airframe logs handled?  Should there be an entry?  If I do the work to overhaul the regulator I'd prefer to have it appear in the logs.

All maintenance must be logged including the preventative maintenance that you as a pilot owner are legal to do. But without checking, I don't recall this as one of the listed tasks. But just as @larryb says above, the repair station will do an entry for the tank & regulator work and then your A&P will do one for the re-install.

Just checked 43.A,c and confirmed the tasks is not preventative maintenance so will at least require A&P supervision.

Edited April 22, 2018 by kortopates

[pwnel]

On 4/22/2018 at 11:01 AM, larryb said:

If you want to fly with it removed you can log it and update the w&b. I did that and then let my shop handle the install sign off. You will get paperwork back from c&l that you can attach to the logs. After reinstall you can remove the temporary w&b form from the poh.

 

Got my cylinder back from C&L today after shipping over there last week.  Great service - thanks for the referral!  I would definitely recommend Jeff at C&L Aero to anyone else reading this thread.  

I'm going to follow your advice and just temporarily update the W&B and fly the plane to the A&P for re-installation later this week.  (Rather than actually strapping the cylinder back where it belongs - ).  It's very nicely packaged and wrapped right now - not feeling like wrestling it back just for a 10 min flight.