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Why have a central heating temperature control on a boiler?

Discussion in 'Plumbing and Central Heating' started by ey143, 26 Dec 2014.

  1. ey143

    ey143

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    What is the purpose of having a temperature control setting or dial on a boiler to control the temperature of the central heating when the thermostat controls the temperature of the room anyway?

    Is the logic that a setting 3 out of 5 (87 degrees) will heat a required room temperature of 23 degrees quicker than a setting of 2 which might heat the water at only 50 degrees and therefore take longer?

    If that is the case, what is the optimum strategy for achieving desired room heat at best economy ie like driving at 58mph is most fuel efficient etc.
     
  2. ALCPlumbing

    ALCPlumbing

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    A room thermostat tells the boiler when to switch off and the thermostat on the boiler controls the temperature of the water coming out of the boiler. I.e. How hot the radiators are to touch?
    Running at a lower temperature is more efficient but every house is different so what works for one may not get another house up to temperature.
    I hope that answers your question. You need both components as they control different things.
     
  3. ALCPlumbing

    ALCPlumbing

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    I didn't read the second part of your post.
    As I said every house is different so it's about finding the right balance between a low flow temperature that is capable of allowing the house to reach the desired temperature. Obviously you also need it hot enough to heat your hot water if you have a cylinder.
    If you have a condensing boiler the combustion gases will condense onto the heat exchanger if the water is returning to the boiler at about 55C or lower.
    If your heating system has been balanced properly there should be about 12-15C difference between the flow and the return so ideally if you can heat your home sufficiently with a flow temp of about 65C you will be utilising the condensing capabilities of your boiler and still heat your hot water enough to avoid legionnaires.
     
  4. ey143

    ey143

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    Thanks I do. Would there be a reason why a plumber who installed a boiler 15 years ago at my parents place did not add a wireless thermostat to the system when instead we only controlled the temperature on the Worcester Bosch boiler itself? He was a decent guy (our corgi neighbour actually).

    We recently had the boiler replaced with a cdi 29kw junior which has a wireless thermostat.

    Also how hot does the boiler boil the water too at the 1-5 settings?
     
  5. ey143

    ey143

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    Another question - since the old cooler water is constantly flowing through the boiler, what does the digital temperature read out reflect because I see it counting down from 80 to 60. Can't be the output as that should be stable?
     
  6. ALCPlumbing

    ALCPlumbing

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    I'm not too hot with all the models of the worcesters. Am I right in thinking that's a combi boiler? If so I think the hot water temperature is preset and the thermostat on the boiler only controls the flow temperature to the heating system.
    In response to your last question is that with the heating running or when you are running the hot water?
     
  7. ey143

    ey143

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    The Worcester we had 15 years ago at my parents house was a combi and the latest one is a condensing.

    My house (last question I referred to) was a Viessmann, pic below.



    [​IMG]
     
  8. JohnD

    JohnD

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    There is no need for a room stat to be wireless. Wireless ones go wrong more often. I don't know that wireless ones were available 15 years ago.

    If you mean there was no room stat, it was foolish and wasteful of energy. Some old people like to turn the heating on and off by hand as if it was an electric fire. You will occasionally hear from some nutter who says a room stat is no advantage.
     
  9. ey143

    ey143

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    Yes the previous plumber put no room stat in at all and when he took the old chimney boiler out, he removed the old wired room stat. Trying to understand why he didn't put one in with the old boiler in 1995.
     
  10. JohnD

    JohnD

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    Nutter who didn't read the instructions or wanted to save £7 and the work of running a new cable.

    Or perhaps somebody told him not too in case it spoiled the decoration.
     
  11. D_Hailsham

    D_Hailsham

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    Does this refer to the Viessmann?

    Do you have weather compensation?

    Which controls do you have?
     
  12. ey143

    ey143

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    No I referring to be all Worcester Bosch boiler which was replaced in 1995 at my parents place. Anyhow that was replaced a few years ago again with a better Worcester Bosch and this time with a wireless thermostat. My terence get the cold weather payment yes.
     
  13. Dan Robinson

    Dan Robinson

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    That my friend is an oxymoron if ever I saw one. ;)
     
  14. BingoBongo

    BingoBongo

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    top yer pressure up before youre back on here on new years eve with no heating and hot water :LOL:
     
  15. ey143

    ey143

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    I know I need to, and I do at my parents place but I'm not sure which one to turn on this boiler. Worried I might get it wrong.

    I think TCCHeating said in another thread it's the valve on the silver thing at the right hand side. I'm not sure which one. Why are there two is it because I have sectional heating in the house for different floors? If so does the pressure indicator referred to the whole system or one of the sections only?

    [​IMG]
     
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