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  1. #11
    colhel's Avatar
    colhel is online now Registered User
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    Will this do? if you scroll down you'll 3/32" which is about 2.4mm.
    No connection with the company... I just work there!

  2. #12
    electrosys is offline Registered User
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    If I were plumbing-in a 2mm ID copper tube for oil - I wouldn't (if you get my drift) ...
    I'd much prefer to run the lion's share of the tube in (say) 4mm ID, and fit a reducer to 2mm ID only at the appliance end. Any Tee-offs etc., all in the larger bore pipe.

    My reasoning is that there would be less of a viscosity problem in cold weather with the larger bore pipe, plus it is probably less likely to suffer damage. And it is probably much easier to source.

    If there's a reason why this is a bad idea, perhaps someone would kindly let me know - 'cause I can't see one.

  3. #13
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    Quote Originally Posted by electrosys View Post
    If there's a reason why this is a bad idea, perhaps someone would kindly let me know - 'cause I can't see one.
    a) 2mm is easy and cheap to get hold of
    b) 2mm is robust and has similar wall thickness to slightly larger bore
    c) 2mm is what the manufacturers specify.
    d) I have never (with modern fuels) had an issue with flow problems in cold weather.
    e) if you do use 4mm, don't expect any onsite warranty cover.
    Last edited by David2452; 26-12-11 at 19:20.
    East Coast Marine Heating & Electronics, Webasto, Wallas & Mikuni dealer

  4. #14
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    Copper car brake pipe is very small bore, that is what I used for part of the pipe run on mine.
    20 mtrs seems like a very long run!
    C_W
    Holiday Flat to let in Millport , pm for details.

  5. #15
    pcatterall is offline Registered User
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    Thanks again. I dont really understand the hydraulic flow side of this. The 2mm pipe from the supply to the pump ( no, I only need a couple of meters for each installation not 20 ) The manufacterers specify 2mm and not more than a certain length or rise.
    I can see that 4mm would take much longer to prime than 2mm and that the pump may not be able to 'lift' the extra volume of fuel, sticking a section of 2mm in the system would only seem to help by limiting the fuel flow.
    Perhaps I am not seeing things clearly?
    Colhel...? is there a link that I am not seeing as well?

  6. #16
    Anchorite is offline Registered User
    Location : FRANCE nr. Lyons
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    Post Chapter and verse

    From the Webasto manual: Air or gas bubbles will accumulate in lines with an internal diameter of more than 4 mm and these will cause malfunctions whilst the heater is operating if the lines sag or are routed downwards...
    Re the 2 mm ID clear plastic tube (Web supply): what is the max ambient temperature for this material? The fuel inlet is very close to the exhaust outlet!

  7. #17
    colhel's Avatar
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    Quote Originally Posted by pcatterall View Post
    Perhaps I am not seeing things clearly?
    Colhel...? is there a link that I am not seeing as well?

    That's because I forgot to put it in It's flexible stuff for model aircraft installations. Just scroll down a little.

    http://www.justengines.co.uk/acatalo...g_Gear_72.html

  8. #18
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    Thing is, 4mm bore pipe, though double the dia actually is carrying more like four times the weight & volume of fuel and the diameter also allows for much easier backflow, as the pumps are really designed as pushers rather than “suckers” they have difficulty pulling through much more than 2mm consistently and effectively. If we are discussing 2m of pipe for each install we really are talking bus fares here and coming close to spoiling the ship for a hap’orth of tar. You are looking for a solution to a problem that does not really exist by simply not using the right cupro nickel stuff, for goodness sake, I would be charging about 6.00 for that run as part of an install, and that’s at my normal dealer prices. The stuff on the model site is three times the price of the stuff I use from Webasto and Mikuni.
    Last edited by David2452; 27-12-11 at 11:38.
    East Coast Marine Heating & Electronics, Webasto, Wallas & Mikuni dealer

  9. #19
    SAMYL is offline Registered User
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    Try a local dental equipment supplier, they uaually have loads of small bore tubing of different sizes.
    Last edited by SAMYL; 27-12-11 at 11:38.

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