Boiler firing with no apparent setpoint request

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  • AutoTrialer
    Automated Home Lurker
    • Feb 2016
    • 9

    Boiler firing with no apparent setpoint request

    Anyone else experiencing this? I have setpoints for the ground floor @15 for all zones (7) and upstairs @10 all zones (5). Hot water set for twice a day to @60. Normally no issues. For the last day the boiler is continually calling for heat. I can't detect any real heat through the radiators but there is an overall rise in heat in the house and my gas meter is showing prolonged boiler activity. I'm still on the old app and wifi software so can't see that being the issue. Any thoughts?
  • DBMandrake
    Automated Home Legend
    • Sep 2014
    • 2361

    #2
    Originally posted by AutoTrialer View Post
    Anyone else experiencing this? I have setpoints for the ground floor @15 for all zones (7) and upstairs @10 all zones (5). Hot water set for twice a day to @60. Normally no issues. For the last day the boiler is continually calling for heat. I can't detect any real heat through the radiators but there is an overall rise in heat in the house and my gas meter is showing prolonged boiler activity. I'm still on the old app and wifi software so can't see that being the issue. Any thoughts?
    Have you been around the house and actually verified the set points on every individual HR92 is what the control panel claims ? Under certain rare circumstances they can get out of step with each other so an HR92 may actually be set to an increased set point even though the controller thinks it isn't.

    This can happen for example if you have a zone with repeated identical set points - say you have a room you don't use much so you have it scheduled for 10 degrees multiple times a day and just manually turn it up when you want to use the room, relying on the next 10 degree scheduled set point to turn it down again. This can occasionally cause the HR92 to not be turned down as expected even though the controller reports it is turned down. This situation will persist until either you manually adjust the HR92 or a set point other than 10 degrees is scheduled or set from the control panel. (This includes any quick actions that may change the temperature in the zone) So if all your set points for the zone are the same, this problem can potentially persist forever without intervention.

    Checking the set point directly on every HR92 will confirm if this is the issue or not.
    Last edited by DBMandrake; 22 November 2017, 12:06 PM.

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    • AutoTrialer
      Automated Home Lurker
      • Feb 2016
      • 9

      #3
      I doff my hat to your knowledge and thanks for the response. I have checked all the HR92 and lo and behold the issue has stopped. The checkpoint schedule was as you describe it, set to the same value for upstairs rooms with 4-5 checkpoints of the same value for each day. I'll now look at varying the schedule by a degree or two to avoid such a situation happening again. Many thanks.

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      • DBMandrake
        Automated Home Legend
        • Sep 2014
        • 2361

        #4
        Originally posted by AutoTrialer View Post
        I doff my hat to your knowledge and thanks for the response. I have checked all the HR92 and lo and behold the issue has stopped. The checkpoint schedule was as you describe it, set to the same value for upstairs rooms with 4-5 checkpoints of the same value for each day. I'll now look at varying the schedule by a degree or two to avoid such a situation happening again. Many thanks.
        Even half a degree is enough. As long as you don't repeatedly use the same set point in a row it won't happen. So if you want it to always be say 10 degrees(ish) and periodically automatically cancel manual overrides for you (which I assume is your intention) just alternate between for example 10 and 10.5.

        I actually have a few zones with repeated set points where they go to 5 degrees at 10pm but then again at 12pm. This is in case I manually turned them up after 10pm but forget to turn them down again before bed, they will automatically go back down at midnight. However the problem you describe is very rare and with my schedule the issue would last at most until the following morning when the set point changes again - I don't have any zones where the same set point is used repeatedly through the entire day without any variation in set point - that's what I'd definitely avoid.
        Last edited by DBMandrake; 22 November 2017, 09:51 PM.

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