Not strictly a Tado question…

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Notascoobie
Notascoobie ✭
in General Questions & Topics

…more of a boiler question. I have range rated my boiler(Worcester 38cdi classic)down to its minimum power output of 9.4kw. How is it then that I often see spot readings of well below 9.4kw on my smart meter monitor, eg: 2.445kw as shown below.

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I have my extension kit connected to the ems bus connections in the boiler, but surely Tado can’t modulate the boiler output down below its minimum output…can it?

Answers

  • DM932187
    DM932187 ✭✭✭
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    The boiler will switch off below its range.
  • Notascoobie
    Notascoobie ✭
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    Wouldn’t that mean that my spot usage reading on th smart meter monitor would be zero then? The boiler is the only gas appliance in the house.

  • DM932187
    DM932187 ✭✭✭
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    I guess it depends how spot is the spot.

    Boilers switch off when the load is below their lowest output and 9.4kw is not that low. I’d expect it to cycle in milder weather.
  • Notascoobie
    Notascoobie ✭
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    Yep, I agree. But... if the boiler is running, as I burning gas, and its minimum power output is 9.4Kw, then surely the monitor should be showing 9.4Kw, or zero if its off? It's these lower readings I can't get my head around. Apologies if I'm being dense.
  • DM932187
    DM932187 ✭✭✭
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    I’m going to hazard a guess that the answer lies in your spot reading being in kWh but your boiler power output is in kW.

    That said, I don’t disagree that if at any particular moment you’re using 0 kW, you are by definition, using 0 kWh However, I guess it’s possible that the meter constantly averages your kW usage over say an hour, to come up with ‘current’ kWh.
  • Notascoobie
    Notascoobie ✭
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    Ah, you might be on to something there. The manual for the monitor says that for electricity the spot reading is updated every 3 secs, but for gas it is only updated every 30 mins, and displays the average for the last 30 min time period. So I’m guessing if the boiler was ‘on’ for the full 30 mins then it would show 9.4Kw. If it’s showing 2.4Kw, then that would mean the boiler had actually been on for approx 25% of the 30 min period = 7.5 mins.

    Thanks for your observations, that makes sense to me now.

  • davidlyall
    davidlyall ✭✭✭
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    If you've reduced boiler output to 9.4KW that will be 9.4KW over one hour.

    i.e. in your example, if it was on and producing heat for 30 minutes, you'd see usage of 4.7KWh

    HTH

  • Notascoobie
    Notascoobie ✭
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    @davidlyall , I'm not sure that's correct. The monitor is taking an average of the gas usage every 30 mins, not every hour.. if the boiler is outputting 9.4Kw for the full 30 mins, then the average output over those 30 mins is 9.4Kw. The monitor would need to to be taking hourly readings, and the boiler on for 30 mins then off for 30 mins for the hourly average to be 4..7Kw. I am talking about Kw here and not Kwh.

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