Results 1 to 14 of 14

Thread: Do 20 lb propane cylinders use back seating valves?

  1. #1
    Join Date
    Nov 2009
    Location
    Arizona
    Posts
    2,935
    Post Thanks / Like

    Do 20 lb propane cylinders use back seating valves?

    I always assumed the small 20 lb BBQ and RV cylinders used back seating valves and I can find some confirmation and opinions either way but nothing from an official source.
    Miller Challenger 172
    Miller Thunderbolt AC/DC 225/150
    Miller Maxstar 150 STL
    Victor 100C
    Victor Journeyman
    Oxweld OA
    Harris O/A
    Smith O/A little torch

    No, that's not my car.

  2. #2
    Join Date
    Mar 2018
    Location
    Clovis California
    Posts
    5,758
    Post Thanks / Like

    Re: Do 20 lb propane cylinders use back seating valves?

    The propane type valves typically is all on so seat does not leak. But could have changed over the years to a better valve.
    You need to see if your valve want to be fully on.

    Dave

    Quote Originally Posted by bigb View Post
    I always assumed the small 20 lb BBQ and RV cylinders used back seating valves and I can find some confirmation and opinions either way but nothing from an official source.

  3. #3
    Join Date
    Mar 2018
    Location
    Clovis California
    Posts
    5,758
    Post Thanks / Like

    Re: Do 20 lb propane cylinders use back seating valves?

    FYI I use the 20lb exchange tanks and have filled at the gas station.
    Exchange when the tank is out of date or the valves leak.

    Dave

    Quote Originally Posted by bigb View Post
    I always assumed the small 20 lb BBQ and RV cylinders used back seating valves and I can find some confirmation and opinions either way but nothing from an official source.

  4. #4
    Join Date
    Jan 2004
    Location
    Brethren, Mi
    Posts
    2,931
    Post Thanks / Like

    Re: Do 20 lb propane cylinders use back seating valves?

    I am not sure how much the ones I saw today at the exchange really were, the sign says 15# and the 20$ price sign was well scratched over. The supply hose finally sprung a leak after 25 years or so and I had nice chunk of copper line on hand to replace it.
    Attached Images Attached Images  

  5. #5
    Join Date
    May 2014
    Location
    Manitoba Canada
    Posts
    6,811
    Post Thanks / Like

    Re: Do 20 lb propane cylinders use back seating valves?

    Quote Originally Posted by bigb View Post
    I always assumed the small 20 lb BBQ and RV cylinders used back seating valves and I can find some confirmation and opinions either way but nothing from an official source.
    Interesting... my search turns up the same variety of answers. I wonder if it varies between manufacturers or geographical location/local codes?
    The harder you fall, the higher you bounce...

    250 amp Miller DialArc AC/DC Stick
    F-225 amp Forney AC Stick
    230 amp Sears AC Stick
    Lincoln 180C MIG
    Victor Medalist 350 O/A
    Cut 50 Plasma
    Les

  6. #6
    Join Date
    Jun 2008
    Location
    Central California
    Posts
    4,132
    Post Thanks / Like

    Re: Do 20 lb propane cylinders use back seating valves?

    Quote Originally Posted by bigb View Post
    I always assumed the small 20 lb BBQ and RV cylinders used back seating valves and I can find some confirmation and opinions either way but nothing from an official source.
    I have removed and disassembled quite a few propane valves, particularly the older versions no longer legal but even a few newer ones with the fluid level shut-off. My memory isn't the greatest wrt details like this that don't (then) catch my interest but I don't recall seeing any valves that did have back-seating. For two/three days I've been looking for some scrap ones to photograph, but none were readily found, so no pictures today.

    I do recall some valves w/ a diaphragm separating the control from the fluid side, but don't think they were for propane; probably for an industrial Freon.

  7. #7
    Join Date
    May 2014
    Location
    Manitoba Canada
    Posts
    6,811
    Post Thanks / Like

    Re: Do 20 lb propane cylinders use back seating valves?

    This guy is probably more of a lesson in what not to do, but it doesn't appear to have back seating....

    Last edited by whtbaron; 01-30-2022 at 03:36 PM.
    The harder you fall, the higher you bounce...

    250 amp Miller DialArc AC/DC Stick
    F-225 amp Forney AC Stick
    230 amp Sears AC Stick
    Lincoln 180C MIG
    Victor Medalist 350 O/A
    Cut 50 Plasma
    Les

  8. #8
    Join Date
    Nov 2009
    Location
    Arizona
    Posts
    2,935
    Post Thanks / Like

    Re: Do 20 lb propane cylinders use back seating valves?

    I watched that video of the guy taking the valve apart and there are two orings so I wonder if one oring seals the stem in each direction?
    Miller Challenger 172
    Miller Thunderbolt AC/DC 225/150
    Miller Maxstar 150 STL
    Victor 100C
    Victor Journeyman
    Oxweld OA
    Harris O/A
    Smith O/A little torch

    No, that's not my car.

  9. #9
    Join Date
    May 2014
    Location
    Manitoba Canada
    Posts
    6,811
    Post Thanks / Like

    Re: Do 20 lb propane cylinders use back seating valves?

    Not sure... I was wondering the same thing.
    The harder you fall, the higher you bounce...

    250 amp Miller DialArc AC/DC Stick
    F-225 amp Forney AC Stick
    230 amp Sears AC Stick
    Lincoln 180C MIG
    Victor Medalist 350 O/A
    Cut 50 Plasma
    Les

  10. #10
    Join Date
    Oct 2014
    Posts
    1,423
    Post Thanks / Like

    Re: Do 20 lb propane cylinders use back seating valves?

    Quote Originally Posted by bigb View Post
    I watched that video of the guy taking the valve apart and there are two orings so I wonder if one oring seals the stem in each direction?
    They aren't. Too close together. They just travel up and down the smooth bore above the seat. They seal the same open or closed or any position in between. It doesn't even have seats at all for the stem in either direction. Only at the tip for closing off the valve and two orings.

    Just two orings running up/down in the bore. Nothing else above this sealing anything.

    Last edited by danielplace; 02-03-2022 at 10:32 AM.

  11. Likes whtbaron liked this post
  12. #11
    Join Date
    Aug 2012
    Location
    AR
    Posts
    2,264
    Post Thanks / Like

    Re: Do 20 lb propane cylinders use back seating valves?

    Why not call a place that provides propane to residential and industrial customers and ask them?? Or better yet, a company that makes the 20# tanks???

  13. #12
    Join Date
    Oct 2014
    Posts
    1,423
    Post Thanks / Like

    Re: Do 20 lb propane cylinders use back seating valves?

    Quote Originally Posted by shortfuse View Post
    Why not call a place that provides propane to residential and industrial customers and ask them?? Or better yet, a company that makes the 20# tanks???
    Likely to get mixed responses there as well depending on just how intelligent the individual that answers your question is.

    That probably would not be ok for a gas valve to be leaking just because someone didn't open it all the way.


    Think about that question for 1/2 second. Nope they DO NOT have to be back-seated. Lol.

    "Darn it, seems the wife only opened the barbecue tank valve 1/2 way and lit it 20 minutes later and blew the back of the house out".

    Fuel gases would have different rules than for inert gases.


    The video posted shows one being dissected. It doesn't have any seats above the one at the tip that closes off the flow.

    Those orings would have been dead centered in a taper if they were seating into/against a taper. There is no other brass on the stem sealing just the threads and maybe a top seal but nothing valve operated at each end of the threads travel. They would be the stops if they were there but they don't exist.
    Last edited by danielplace; 02-03-2022 at 05:28 PM.

  14. #13
    Join Date
    Nov 2009
    Location
    Arizona
    Posts
    2,935
    Post Thanks / Like

    Re: Do 20 lb propane cylinders use back seating valves?

    Quote Originally Posted by danielplace View Post

    Think about that question for 1/2 second. Nope they DO NOT have to be back-seated. Lol.

    "Darn it, seems the wife only opened the barbecue tank valve 1/2 way and lit it 20 minutes later and blew the back of the house out".
    .
    That is the likeliest reason they don't need to be back seated as how could you make that a requirement for the general public who is not even smart enough to know you don't get in and out of your vehicle when fueling? I was only wondering if perhaps one did leak a bit at the stem if back seating it would stop it. I have one now that leaks when opening but seems to stop when fully open, at least I get a big whiff when opening it that goes away once opened. It's very old and expired and is just about empty, will give it to Blue Rhino for a fresh one soon.
    Miller Challenger 172
    Miller Thunderbolt AC/DC 225/150
    Miller Maxstar 150 STL
    Victor 100C
    Victor Journeyman
    Oxweld OA
    Harris O/A
    Smith O/A little torch

    No, that's not my car.

  15. Likes whtbaron liked this post
  16. #14
    Join Date
    Sep 2014
    Posts
    2,253
    Post Thanks / Like

    Re: Do 20 lb propane cylinders use back seating valves?

    Quote Originally Posted by bigb View Post
    That is the likeliest reason they don't need to be back seated as how could you make that a requirement for the general public who is not even smart enough to know you don't get in and out of your vehicle when fueling? I was only wondering if perhaps one did leak a bit at the stem if back seating it would stop it. I have one now that leaks when opening but seems to stop when fully open, at least I get a big whiff when opening it that goes away once opened. It's very old and expired and is just about empty, will give it to Blue Rhino for a fresh one soon.
    It could just be the wear is right at the spot where it opens, and then hits fresh meat as you back it out. I think they seal because I had a few forklift tanks that leaked and if you backed them out all the way they would stop too.

    That is one of the things I was wondering about Oscars three acetylene tanks all connected together.

    I am assuming he has high pressure check valves on each tank, but even so if one of the check valves went bad and you hit an empty tank with a couple hundred pounds from a new tank what kind of heat would you generate?


    Sincerely,

    William McCormick
    If I wasn't so.....crazy, I wouldn't try to act normal, and you would be afraid.

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  
Page generated in 1,652,974,228.12034 seconds with 15 queries