Optimum boiler anti-cycle setting with Evohome

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  • kevinsmart
    Automated Home Ninja
    • Sep 2018
    • 257

    Optimum boiler anti-cycle setting with Evohome

    My Intergas HRE40SB boiler anti cycle parameter P is set to 10mins, the default is 5mins.

    I’m wondering what the optimum setting, from an efficiency point of view, is for Evohome OpenTherm when at low load?

    At lowish loads the boiler heats (5) until the requested flow temperature+5C, ventilates (3), shuts down (1) for the anti-cycle time (10 mins). The flow temp can drop 20C or more in this time. That’s why I am wondering whether 10min is too long.

    At even lower loads. Evohome deploys a low load control algorithm (on/off), Evohome can interrupt the anti-cycle by requesting 10C flow temperature (off). Boiler switches to Pump Overrun (0) until a new temperature request (on). The boiler may then repeat the cycle.

    So in this mode the boiler can ignite/ventilate more than once in a 10min interval.
  • m112
    Automated Home Jr Member
    • Oct 2016
    • 22

    #2
    Hello

    Ive got an intergas boiler too just a diffent model.from testing it appears that anticycle is ignored by opentherm from what ever reason.

    But this is only my personsl opinion

    Comment

    • kevinsmart
      Automated Home Ninja
      • Sep 2018
      • 257

      #3
      The boiler will cycle with Opentherm. When the flow temperature reaches 5C above the requested temperature, it will shutdown keeping the pump running (1).

      See my description above of the low load control algorithm which comes into play.

      I set the anti-cycle time back to the 5min Intergas default, which results in less flow temperature reduction.

      Comment

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