Heating Partial Load

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts
  • bruce_miranda
    Automated Home Legend
    • Jul 2014
    • 2307

    #46
    Evohome already offers OpenTherm - which does indeed adjust the CH temp based on the zone demand %.

    Comment

    • rarrarrar
      Automated Home Jr Member
      • Oct 2011
      • 19

      #47
      Originally posted by bruce_miranda View Post
      Evohome already offers OpenTherm - which does indeed adjust the CH temp based on the zone demand %.
      Not in UK and some forum posts have suggested issues.

      Comment

      • rs1987
        Automated Home Jr Member
        • Nov 2019
        • 44

        #48
        Originally posted by rarrarrar View Post
        Boiler max anti-cycle time D.002 is set to 6 mins ( default is 20)
        EvoHome has min burn time of 3 mins and 6 cycles per hour.
        Although short cycle times are in-efficient , in a large Victorian house with not great insulation and individual room controls waiting 20 mins before heat comes through is not acceptable.
        I put my minimum burn time up to 5 minutes and the anti-cycle timer on 10 mins. The shorter cycle was just not working as effectively. I'd rather have a 0.5 degree overshoot than a 0.5 degree undershoot.

        Comment

        • bruce_miranda
          Automated Home Legend
          • Jul 2014
          • 2307

          #49
          Originally posted by rarrarrar View Post
          Not in UK and some forum posts have suggested issues.
          Issues Like?

          Comment

          • Wlife
            Automated Home Lurker
            • Jan 2020
            • 8

            #50
            has anyone figured out evohome opentherm r8810 with a worcester boiler yet? tried the nefit converter couldn't control the boiler firing so went back to bdr91. I too was trying to improve cycling/efficiency I've since changed some settings and seeing how it goes.

            Comment

            • bruce_miranda
              Automated Home Legend
              • Jul 2014
              • 2307

              #51
              Originally posted by Wlife View Post
              has anyone figured out evohome opentherm r8810 with a worcester boiler yet? tried the nefit converter couldn't control the boiler firing so went back to bdr91. I too was trying to improve cycling/efficiency I've since changed some settings and seeing how it goes.
              With the nefit converter are you able to see variable Target Flows being set for the boiler based on OT? Because the work around which I previously used when I too couldn't get my Vaillant to fire with the R8810 was to set up the system with OT for boiler control and then a 2 zone valve configuration on Evohome. So Evohome would open the CH Valve using a BDR91 and then I would use the zone valve micro switch to fire the boiler, while the R8810 was dynamically setting the Target temperature.
              This all worked quite well, till I figured out how to get the R8810 to fire the boiler directly.

              Comment

              • Wlife
                Automated Home Lurker
                • Jan 2020
                • 8

                #52
                Originally posted by bruce_miranda View Post
                With the nefit converter are you able to see variable Target Flows being set for the boiler based on OT? Because the work around which I previously used when I too couldn't get my Vaillant to fire with the R8810 was to set up the system with OT for boiler control and then a 2 zone valve configuration on Evohome. So Evohome would open the CH Valve using a BDR91 and then I would use the zone valve micro switch to fire the boiler, while the R8810 was dynamically setting the Target temperature.
                This all worked quite well, till I figured out how to get the R8810 to fire the boiler directly.
                thanks for the response Bruce.

                Yes I could see variable flow targets on the boiler display and it wouldn't continuously climb as it does with the bdr91 controlling it.
                Forgive my lack of knowledge my setup is a combi I do not have any zone valves I am using hr92s on rads. I am open to adding the zone valve it seems a good workaround are their any drawbacks to this method?
                How did you get your boiler to fire directly with the R8810? my boiler is a WB life 8000 combi.
                Would you say the CH/Evohome is working better now via opentherm, I read the financial savings are slim but even from a comfort/function point of view it must be better.

                Comment

                • bruce_miranda
                  Automated Home Legend
                  • Jul 2014
                  • 2307

                  #53
                  you dont need the actual zone valve. You just need to configure Evohome to think you have a CH and DHW zone valves and then you use the BDR91s to fire the boiler.

                  Comment

                  Working...
                  X