difference between 3 port & mid position valves

Discussion in 'Plumbing and Central Heating' started by angelf, 26 Apr 2010.

  1. angelf

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    what is the difference between a 3 port valve & a mid position motorised valve?

    Can one be replaced with the other?

    If not why not?
    Cheers
     
  2. Mr Smyth

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    A 3-Port valve lets you select HW or Htg whereas a mid position valve lets you select HW, Htg or both HW and Htg.

    Yes you can change a 3-Port to a mid position valve but there will be some simple changes to your wiring.

    Hope this helps
     
  3. 45yearsagasman

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    Both of these have "3 Ports" ie inlet port and hw and heating outlet ports.
    A mid position valve is able to allow water to flow to HW only,CH only and to both at once by holding the valve in the Mid Position,These valves normally have 5 wires. A 3 port diverter normally has 3 wires and can only supply CH on its own or HW on its own but not both together.These valves as such are interchangeable with some wiring alterations.
     
  4. angelf

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    thanks Mr Smyth & 45 year gas man
     

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