Evohome - Changing Parameters

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  • HenGus
    Automated Home Legend
    • May 2014
    • 1001

    Evohome - Changing Parameters

    Yesterday, I changed the parameters for the Evohome HW Kit from 60 to 65C in the settings menu. Everything appears to have been set up correctly but the hot water is still only heating up to 60C. I must be missing something but I am not sure what.
  • Rameses
    Industry Expert
    • Nov 2014
    • 446

    #2
    Depends. What is the boiler set at? If you have the boiler at 60 then this will be the max in. . . The differential also will try to get the average to the desired temp. So it depends on when you looked at the screen (ie it could have been on the up?). Check the boiler limit first.
    getconnected.honeywell.com | I work for Honeywell. Any posts I make are purely to help if I can. Any personal views expressed are my own

    Comment

    • HenGus
      Automated Home Legend
      • May 2014
      • 1001

      #3
      Thanks. The HW kit is fitted to one of the two motorised valves on an OSO unvented HW tank ( the second motorised valve is for CH). Checking today, the hot water is within the range 55 to 60 Cwhich indicates, to me at least, that changed differential setting is working. Before the HW kit was fitted, temp control was managed via the temp selector in the base of the tank. The instructions say that this can be set in the range 40 to 70C. There is a safety cut-out at 85C. I had assumed that the HW kit sensor would have eliminated the need for/by-passed the cylinder thermostat.

      I am trying to contact my installer but he seems to have gone 'silent and deep'.

      Comment

      • SensibleHeatUK
        Moderator
        • Feb 2009
        • 228

        #4
        You should never bypass the combined control/high-limit stat on an unvented cylinder as it is an integral safety device that is required under the regs. You can turn up the control stat so it is higher than your Evo setpoint so that Evo stays in control.
        Sensible Heat
        SensibleHeat.co.uk

        Comment

        • HenGus
          Automated Home Legend
          • May 2014
          • 1001

          #5
          Originally posted by SensibleHeatUK View Post
          You should never bypass the combined control/high-limit stat on an unvented cylinder as it is an integral safety device that is required under the regs. You can turn up the control stat so it is higher than your Evo setpoint so that Evo stays in control.
          Thanks - my mistake. I assumed wrongly that the high-limit stat was separate from the control stat (which the Evohome ssensor replaced) on the tank when in fact all 3 stats are in series. I will give the control stat a tweak as you suggest.

          Comment

          • HenGus
            Automated Home Legend
            • May 2014
            • 1001

            #6
            Update. I adjusted the control stat on the OSO cylinder and it achieved absolutely nothing. The hot water reaches 60C and that is it. Out of interest, does anyone know what the upper limit of the HW Kit sensor is? My installer is coming back to take a look. I am just hoping that he hasn't inadvertently cut off the unvented tank safety systems.

            Comment

            • SensibleHeatUK
              Moderator
              • Feb 2009
              • 228

              #7
              When your tank reaches 60 degrees then you need to check two further things:
              1) is your Hot Water Honeywell Relay Module still on (green LED still lit)?
              2) is your hot water 2-port valve still open?

              This will tell you if it is an Evo issue (module switching off at 60 degrees), a tank thermostat issue (valve closed so likely to be the cylinder stat), or all on/open but tank not getting hotter (which suggests your boiler stat is set too low and limiting the temperature your hot water can reach).
              Sensible Heat
              SensibleHeat.co.uk

              Comment

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