Refilling RV habitation gas

Discussion in 'American RV's' started by Lumbago, Jan 27, 2011.

  1. Lumbago

    Lumbago Read Only Funster

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    When refilling a habitation fixed gas tank on a Winnebago RV, I've heard that I should open the overflow gas valve which is situated near the filler cap, and wait until liquid gas comes out. When the liquid gas comes out it is full. Is this necessary and correct as it appears to waste gas? Thanks for your help.
     
  2. madbluemad

    madbluemad

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    It most definitely doesn't seem right to me. The pump will automatically switch itself off when the tank is full.
    Jim
    :Smile:
     
  3. scotjimland

    scotjimland Funster Life Member

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    It is not absolutely necessary but is advised as it guarantees you won't overfill in the event of the auto shut off valve failing ..

    you only need to 'crack' open .. the gas lost is negligible ..

    Put it another way, it is the ONLY fail safe way of knowing when your tank is 80% full.

    Overfilling is potentially lethal if liquid LPG enters the take off line to the RV appliances.
     
  4. Brian and Jo

    Brian and Jo Funster Life Member

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    gas

    thanks for that jim,didnt know that,i just fill until the pump gun knocks itself off.i just thought that was the way to do it:Doh: u learn something every day:thumb: regards brian jo and josh
     
  5. Dodgey

    Dodgey Funster

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    I was aware of this but ours is shut tight and I'm a bit concerened at attacking it with tools so tend to rely on the fill shut off and watching the guage, I know where it reads when full so as long as it shuts off at the usual point I'm happy, mind you I'm also aware how unreliable these guages can be:Doh:
     
  6. motor roamin

    motor roamin Funster

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    100% correct Guages and cut off valves can be so far out I wouldn't trust them.

    I think I posted this on RVOC some months ago in depth.

    All the best Rick.
     
  7. Larrynwin

    Larrynwin Funster

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    I always fill until the pump kicks and then check the valve, on three RVs have never seen liguid gas appear but better safe than sorry.
     
  8. johnpengers

    johnpengers Funster

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    As per instructions I slightly open the relief valve on the house tank until the lpg bubbles out,now that seems logical to me but why is there no need to do that when filling the running(engine) tanks.
    Just curious.

    Regards,John P.:thumb:
     
  9. Larrynwin

    Larrynwin Funster

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    Different system it draws liquid gas although engine tanks still only fill to 80%
     
  10. johnpengers

    johnpengers Funster

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    Hi Larry,I understand there are two systems but its still Lpg going into a tank,on the house tank we have a pressure relief valve that we either open it or leave it closed and rely on the pump to shut off but on the running tanks we all rely on the pump to shut off at 80%.I'm just curious why there does'nt seem to be a safety device on the running tanks as there clearly is on the house tank.
    One of lifes mysteries I suppose,just think of the fun we could have debating this issue over loads of Boddingtons Bitter !!!!!!!!:Laughing:

    Regards, john P:thumb:
     
  11. Dodgey

    Dodgey Funster

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    Just a thought but, vehicle tanks are often inside the vehicle so the Yank bleed valve would be a tad dangerous?
     
  12. Larrynwin

    Larrynwin Funster

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    Don't need a bleed valve on engine supply tanks as the system draws off liquid unlike the domestic tank which supplies gas from the liquid.
     
  13. pappajohn

    pappajohn Funster Life Member

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    my thoughts on this overfilling engine tanks malarky......

    if you should overfill, it wont have time to expand as you'll use a hell of a lot in a short time and soon get back to 80% full. :Laughing:
     
  14. damondunc

    damondunc Funster

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    refilling rv domestic tanks

    up to 1996 it was not a legal requirement in the usa to have an auto stop filler fitted (similar to a toilet cistern valve) which is designed to stop the lpg filling the tank at 80% liquid capacity. there are loads of older rv's around that have the potential to be overfilled!
    there are various saftey devices fitted to rv tanks:
    (1)the red needle type sight guage which shows from E to F (f is 80% full) if you look carefully past the F mark you should see 85% and 90%.
    (2) the small brass valve next to the filler (80% valve) when filling the idea is to have the valve slightly open and when the tank is full to safe capacity the jet of vapour will turn to a white jet of liquid. then stop filling and tighten the valve.
    (3) an asme auto stop valve which should stop the filling of the tank automatically at 80% capacity.
    the only problem with this is on early rv's when filling in a petrol station if you open the 80% valve you will end up having a pool of lpg vapour around the rv, lpg vapour is much heavier than air and on a day that is not windy it will just sit there.
    you should try to use at least two of these safety devices when filling always keep an eye on the red needle.
    if the tank is accidentaly overfilled there are saftey valves in all american tanks that will vent the excess pressurised lpg to atmosphere, some are in the base of the tank with a small rubber bung in the end some are part of the stopcock valve (mainly on early ones).
    The real danger of overfilling an lpg tank is the potential of getting liquid lpg into the regulator. and believe me you don't want that to happen. The reason for 80% safe capacity is to allow for heat expansion, if you overfill the tank on a cool evening and then park up on a warm day the safety valve will almost certainly open venting lpg.
    Dunc.
     
  15. johnpengers

    johnpengers Funster

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    Thank you Duncan,thats all I wanted to know !!!!!

    Many Thanks John P,:thumb:
     
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