1. Visiting from the US? Why not try DIYnot.US instead? Click here to continue to DIYnot.US.
    Dismiss Notice

Conventional boiler temperature control

Discussion in 'Plumbing and Central Heating' started by chalkywhite, 11 Feb 2021.

  1. chalkywhite

    chalkywhite

    Joined:
    24 Oct 2007
    Messages:
    204
    Thanks Received:
    33
    Location:
    Berkshire
    Country:
    United Kingdom
    Hi, my Greenstar Ri boiler has a dial temp range of between 35 and 82C.

    I appreciate that the higher temps use more gas but get rooms up to temp quicker and more heat is retained in rads for longer.

    Why then, would I ever want to reduce it?

    Currently set to around three quarters of max dial setting, which would be ~70C, and house heats up nicely. Water tank has its own thermostat which seems to click on and off properly.

    Cheers
     
  2. muggles

    muggles

    Joined:
    28 Oct 2005
    Messages:
    12,943
    Thanks Received:
    2,912
    Location:
    Daventry
    Country:
    United Kingdom
    You've answered your own question. Turning it down will reduce gas consumption, making it cheaper to run.
     
  3. Sponsored Links
  4. chalkywhite

    chalkywhite

    Joined:
    24 Oct 2007
    Messages:
    204
    Thanks Received:
    33
    Location:
    Berkshire
    Country:
    United Kingdom
    What I dont get is that surely over the longer duration on the lower setting it will use as much gas?
     
  5. Razor900

    Razor900

    Joined:
    16 Nov 2007
    Messages:
    5,455
    Thanks Received:
    2,023
    Location:
    Northamptonshire
    Country:
    United Kingdom
    You won't be able to reduce the temp very much assuming it's on an S or Y plan system or you will start getting long hot water cylinder reheat times.

    If you run the rads at 82 degrees when the room thermostat shuts the system off the rads will continue to give heat out and the temp will overshoot the desired value by a few degrees then as it cools it will drop below the required temp and the system will yoyo between too cold and too hot.

    The lower you can run the flow temp and have decent reheat the better
     
    • Like Like x 2
  6. Sponsored Links
  7. muggles

    muggles

    Joined:
    28 Oct 2005
    Messages:
    12,943
    Thanks Received:
    2,912
    Location:
    Daventry
    Country:
    United Kingdom
    Condensing boilers only start to condense (and therefore run at their best efficiency) with a flow temperature of 70°C and a return temperature of 50°C. Higher than that, they stop condensing and start throwing more heat out of the flue. Lower encourages more condensing (lower flue gas temps, more heat going into your system rather than out your wall) but as Razor says you need a high enough flow temperature to heat your cylinder, so it's a compromise
     
    • Thanks Thanks x 1
Loading...

Share This Page