my wood burner won't gravity feed!!!!!!

Discussion in 'Plumbing and Central Heating' started by cornishsteve333, 22 Nov 2014.

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  1. cornishsteve333

    cornishsteve333

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    hello, I've installed a wood burner with a fitted back boiler into my bungalow. I have 28 mm pipe leading from the boiler going up hill for at least the first third of the run to the cylinder, which is a 28mm gravity tank It then runs steeply down into the coil out and back the same way to the boiler. any ideas why it won't gravity feed?
     
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  3. jackthom

    jackthom

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    Is there a high point which could have an airlock?
     
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  4. Norcon

    Norcon

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    If the flow dips down at the cylinder but the return falls constantly then it should thermosyphon.

    If the return has an uphill flow after it leaves the cylinder coil then it will struggle and possibly cancel out the flow force.
     
  5. MrTherm

    MrTherm

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    Gravity through an indirect coil? - coils are intended for circulating pumps!
     
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  6. cross thread

    cross thread

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    reads as your return runs back up ? do you mean it goes up after it leaves the cylinder ?if so it has to fall back to the boiler ignore me if i have misunderstod description
     
  7. Norcon

    Norcon

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    In a bungalow the return should drop back to the floor.
     
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  8. Agile

    Agile

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    I wonder if it was notified to Building Control?
     
  9. oilhead

    oilhead

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    Your cylinder probably is not designed for gravity circulation. You need to order special manufacture for gravity circulation. Alternatively, install a pump controlled by pipe thermostats which will mean you will automatically stop your fire taking away hot water from the cylinder.
     
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  11. Corgigrouch

    Corgigrouch

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    Is the heat leak rad getting hot?
     
  12. petit_pablo

    petit_pablo

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    Do you think it has one?! :LOL:
     
  13. Corgigrouch

    Corgigrouch

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    I was trying to break the habit of a lifetime and be a little diplomatic.... :D
     
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  14. petit_pablo

    petit_pablo

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    No mention of a open vent either!
     
  15. Corgigrouch

    Corgigrouch

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    Maybe THAT'S why the op has gone a bit quiet...
     
  16. Agile

    Agile

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    Sometimes these gravity systems need to get very hot before they will actually start to gravity circulate.

    My friend's system in France is somewhat amusing, when the fire is started it starts gravity circulation is the opposite direction to what is required and what would be expected from the pipe layout.

    But its a pumped system and when the pump is started the flow reverts to the expected direction and then continues that way even if the pump is turned off.
     
  17. Corgigrouch

    Corgigrouch

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    If his flow runs uphill for a third of the way and then down steeply to the cylinder then it is't going to work and depending on how the pipework has been connected there is a fair chance that he will have an airlock where the pipe run changes direction too...
     
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