Easy way to stop hot water circulation in gravity system?

Discussion in 'Plumbing and Central Heating' started by petes, 24 Jan 2007.

  1. petes

    petes

    Joined:
    27 Oct 2006
    Messages:
    10
    Thanks Received:
    0
    Country:
    United Kingdom
    Is there an "easy" (aka cheap) way of stopping the constant hot water circulation in a semi-gravity system. We'll be moving and replacing our boiler in a couple of years time when we do some building work, so i want to avoid splending more than necessary - i.e. converting to a fully pumped system. However, I don't want to stick with the gravity system - such a waste of energy!

    Will just putting a motorised valve in the hw circuit do it - with a tank thermostat to control the valve? How would the boiler thermostat deal with this - just heat up the water in the boiler, which then won't circulate, and then cut out?
    Thx
     
  2. Sponsored Links
  3. Onetap

    Onetap

    Joined:
    19 Jun 2006
    Messages:
    1,845
    Thanks Received:
    191
    Location:
    Essex
    Country:
    United Kingdom
    Put in a 2-port zone valve, as per Honeywell C-plan, wiring details here;

    http://content.honeywell.com/uk/homes/systems.htm

    Note the diagram doesn't show the location of the cold feed and open vent pipes and any new valve must be located so that it will not isolate these from the boiler when it closes.

    If you're not competent with wiring, pay someone who is.

    The best plan would be to upgrade it to S-plan, 2 off 2-port valves; it will save you money on fuel.
     
  4. doitall

    doitall

    Joined:
    8 Jan 2005
    Messages:
    18,999
    Thanks Received:
    1,538
    Location:
    Bath
    Country:
    United Kingdom
    Warning signs if the boiler has been installed with gravity primary circuits then you cannot just stick an obstruction (MV) in the pipe.

    We would need to know much more about the system before you could even consider it.
     
  5. petes

    petes

    Joined:
    27 Oct 2006
    Messages:
    10
    Thanks Received:
    0
    Country:
    United Kingdom
    Thanks for the feedback guys. doitall - how do I know if the boiler is setup as you say - is there something indicative of this? I'm guessing this was my concern - if I stop the gravity circulation, what's the boiler going to boil.....
     
  6. doitall

    doitall

    Joined:
    8 Jan 2005
    Messages:
    18,999
    Thanks Received:
    1,538
    Location:
    Bath
    Country:
    United Kingdom
    As I said more info on the boiler and controls, for starters, a few pics would help as well. Pipes from the boiler and around the cylinder
     
  7. Gas2Air

    Gas2Air

    Joined:
    2 Aug 2004
    Messages:
    1,559
    Thanks Received:
    165
    Country:
    United Kingdom
    Basically you cannot fit a motorised valve on the pipework leading to or on the open vent pipe.

    You need to investigate the pipe layout as said.
     
  8. Sponsored Links
  9. JohnD

    JohnD

    Joined:
    15 Nov 2005
    Messages:
    77,070
    Thanks Received:
    4,516
    Location:
    Crossgates, Europe
    Country:
    Cook Islands
    I know someone with an oldish gravity HW/Pumped CH installation with a thermostatic valve ("Cyltrol Valve") on the return from the cylinder.

    The vent runs from the supply pipe.
     
  10. petes

    petes

    Joined:
    27 Oct 2006
    Messages:
    10
    Thanks Received:
    0
    Country:
    United Kingdom
    Yep - I was thinking about putting the valve on the return - that seems to make sense.....
     
  11. JohnD

    JohnD

    Joined:
    15 Nov 2005
    Messages:
    77,070
    Thanks Received:
    4,516
    Location:
    Crossgates, Europe
    Country:
    Cook Islands
  12. Onetap

    Onetap

    Joined:
    19 Jun 2006
    Messages:
    1,845
    Thanks Received:
    191
    Location:
    Essex
    Country:
    United Kingdom
    The advantage of the Honywell type installation is that the zone valve is operated by the time control AND (logical AND) the cylinder thermostat, wired in series. The end switch on the zone valve operates the boiler.

    The boiler is disabled when the water is at the set temperature.

    The boiler is enabled by a HWS OR heating demand. With the S-plan the two end limit switches are wired in parallel.
     
  13. Bigburn

    Bigburn

    Joined:
    20 Dec 2006
    Messages:
    135
    Thanks Received:
    0
    Country:
    United Kingdom
    All fine and dandy Onetap but we still dont know the make and model of the boiler system and until we know its best not advise a possible layman on the use of valves or such like.
     
  14. DIYnot Local

    DIYnot Local

    Joined:
    3 Sep 2019
    Country:
    United Kingdom

    If you need to find a tradesperson to get your job done, please try our local search below, or if you are doing it yourself you can find suppliers local to you.

    Select the supplier or trade you require, enter your location to begin your search.


    Are you a trade or supplier? You can create your listing free at DIYnot Local

     
Loading...

Share This Page