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Discuss Weather compensation sensors in the Central Heating Forum area at

  1. JLS

    JLS Member

    I've picked up a Worcester Fw100 programmer for a new boiler install but it didn't come with a weather compensation sensor, are all sensors equal or will I have to source a Worcester sensor for it to work? If so is there a specific one I need to get? TIA
  2. ShaunCorbs

    ShaunCorbs S. Mod Trusted Plumber GSR Top Contributor!!

    It should come with one best phone up your supplier and get them to send you one
  3. kris

    kris Trusted Plumber GSR

    Defo best to stick to Worcester sensors although open therm is open therm ,
  4. heatservice

    heatservice Member

    Open therm is not Open therm as WB boilers are not compatable with NEST so Im hearing.
  5. JLS

    JLS Member

    Thanks all for the input, unfortunately it was bought cheap off ebay. Still live and learn.
  6. Gasmk1

    Gasmk1 GSR

    only cost about £30
  7. Matchless.plumb

    Matchless.plumb Trusted Plumber GSR

    oh is that true nest isnt compatible with wb boilers in general?
  8. heatservice

    heatservice Member

    Apparently, NEST will work OK as a wireless /internet control for WB boilers but is not compatible when it comes to open therm, the part that is required by Boiler Plus.
  9. S.P.S.

    S.P.S. GSR

    When you say the open therm part is the bit required by boiler plus, where have you read that? All I have read is that it must be a smart control woth automation and optimisation.

    My understanding of this is - the ability to learn/adapt to weather/usage.

    I haven’t read anything about the smart control having to control the flow temperature by way of load compensation.

    I’m just intruiged to see if I’ve got it right or miss interpreted something, that’s all!


  10. heatservice

    heatservice Member

    Have a look at PB Plumber video on YouTube "What is Boiler Plus ?" (sorry I couldn't post the link with my Smart tv)
  11. doitmyself

    doitmyself Well-Known Member

  12. S.P.S.

    S.P.S. GSR

    So I was correct in my thinking? Opentherm is not a requirement.
    Open therm is a way to encorporate load compensation on compatible boilers.
    IE controls flow temperature based on the demand.

    Optimisation and automation are just ways to reduce the amount of time and the buildings temperature based on external factors, such as occupancy and usage. IE a learning thermostat like NEST or HIVE.
    But this doesn’t mean it has to directly control the flow temperature of the boiler based on demand, just reducing when it fires to a more effience use.

    Unless I am reading all this wrong?

    Again, I’m an only looking for clarification on how I perceive it. If I am wrong on this, can you explain how?

    Thanks in advance.

  13. heatservice

    heatservice Member

    Im glad to be retired from it all, looks like your being asked to walk through a mine field wearing a blindfold with your fingers in your ears for good measure, good luck with that.
    • Agree Agree x 2
    • Funny Funny x 1
  14. doitmyself

    doitmyself Well-Known Member

    You have to have the correct sensor. The working component in a sensor is a Negative Temperature Coefficient resistor (NTC), i.e. a device whose resistance increases as the temperature decreases. Manufacturers do not all use a NTC with the same resistance/temperature curve so you are normally stuck with the manufacturer's product - unless you can find out which NTC they use and can obtain one from another source.
  15. YorkshireDave

    YorkshireDave Plumber

    Specifically, one of the correct resistance (IIRC 100 ohms) but in the reqd temperature range as linear response as possible. None are truly linear tho. :rolleyes:

    Tis a strange deal this. A requirement to fit controls, but they are of little value when the homeowner has no inkling how or why they work. Then you factor in the inescapable fact that few installers understand them either and you end up, potentially, using more energy...

    IMHO, it would have made far more sense to have made it mandatory for all installers to understand controls and then to have incentivised them to educate users. It woudl have been slower but it would be a solid foundation of knowledge and professionalism as opposed to the current box ticking fiasco...

    Hey ho, welcome to an enlightened UK...
    • Like Like x 3
    • Winner Winner x 1
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