Heat Sink Radiator

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts
  • Mickjohn
    Automated Home Sr Member
    • Mar 2015
    • 68

    Heat Sink Radiator

    Hi
    I have an 8 Rad system....7 with Evohome HR92’s on and one rad in bathroom acting as a heat sink ( lock shield valves ) all working fine.....not sure i should have said that anyway I understand need for heat sink rad on system that just has thermostatic valves in case all close and boiler is still running but on evohome if all HR92’s are shut then boiler shouldn’t run so could I add HR92 to the bathroom rad which is acting as the heat sink rad

    Hot water is heated from a separate instant water heater.

    Many thanks in advance

    Mick
  • anniesboy
    Automated Home Sr Member
    • Aug 2019
    • 71

    #2
    i had a new system installed last year,initially the plumbers planed to install my bathroom radiator exactly as you describe.

    I explained I wanted HR92s on all radiators (10),which was easily achieved by installing a by pass valve,this was installed in my loft along with the boiler.

    I guess you need the same,however I am not a plumber ,Im sure someone else will clarify or correct if I'm wrong

    I like you have water heated via immersion heater.
    Last edited by anniesboy; 18 September 2020, 05:46 PM.

    Comment

    • CT1
      Automated Home Guru
      • Apr 2016
      • 189

      #3
      I have HR92s on all radiators and my boiler includes an ABV. The system has been working without problems for 6 years. Fitting an external ABV might be necessary depending on your boiler but should not be difficult to install.

      Comment

      • filbert
        Automated Home Guru
        • Oct 2017
        • 161

        #4
        Originally posted by Mickjohn View Post
        Hi
        .... I understand need for heat sink rad on system that just has thermostatic valves in case all close and boiler is still running but on evohome if all HR92’s are shut then boiler shouldn’t run so could I add HR92 to the bathroom rad which is acting as the heat sink rad
        Mick
        I have the same question. Why would the pump or boiler run when the valves are all shut? Especially an old fashioned system like mine (Ideal Mexico, no fancy controls). I just can’t understand why any sort of bypass would be needed.

        Comment

        • Mickjohn
          Automated Home Sr Member
          • Mar 2015
          • 68

          #5
          Originally posted by anniesboy View Post
          i had a new system installed last year,initially the plumbers planed to install my bathroom radiator exactly as you describe.

          I explained I wanted HR92s on all radiators (10),which was easily achieved by installing a by pass valve,this was installed in my loft along with the boiler.

          I guess you need the same,however I am not a plumber ,Im sure someone else will clarify or correct if I'm wrong

          I like you have water heated via immersion heater.
          Thank you for reply seems by pass valve will be the way to go btw i have instant water heater not emersion heater

          Mick

          Comment

          • anniesboy
            Automated Home Sr Member
            • Aug 2019
            • 71

            #6
            Here is a link to why a bypass is installed.

            Comment

            • BuxtonJim
              Automated Home Jr Member
              • Aug 2018
              • 45

              #7
              I'd be thoughtful about that. My boiler apparently has an ABV but, as belt and braces, I use a large towel rad as a bypass in case of pump overruns.
              The bonus is that towels are always bone dry.

              Comment

              • Mickjohn
                Automated Home Sr Member
                • Mar 2015
                • 68

                #8
                Thank you for the above replies much appreciated but instead of ripping up floor boards to fit an automatic bypass valve what about setting a custom schedule at set point say 5 degrees add all present HR92's ( in summer) and install a single zone thermostat (Y87RF) in bathroom and bound to my evohome controller.
                Wouldnt that effectivley control the bathroom rad? or am I missing something?

                Many thanks in advance

                Mick

                Comment

                • DBMandrake
                  Automated Home Legend
                  • Sep 2014
                  • 2361

                  #9
                  I don't understand why you would need to rip up your floor boards to install an automatic bypass valve. They're usually installed within about a metre of the boiler so unless you have a very short pipe run from the boiler before the pipes disappear into the floor installing an ABV shouldn't be a problem.
                  Last edited by DBMandrake; 23 September 2020, 09:20 PM.

                  Comment

                  • DBMandrake
                    Automated Home Legend
                    • Sep 2014
                    • 2361

                    #10
                    Originally posted by filbert View Post
                    I have the same question. Why would the pump or boiler run when the valves are all shut? Especially an old fashioned system like mine (Ideal Mexico, no fancy controls). I just can’t understand why any sort of bypass would be needed.
                    Most boilers have pump overrun so when the boiler demand signal is turned off (BDR91 etc) the pump will continue to run for a few minutes. If all the valves are closed and there is nowhere for that overrun to flow the pump will not be very happy trying to pump into a dead end...

                    Also you can't trust the Evohome system to never allow the boiler relay to turn on when all HR92's are closed and blocking water flow - it actually happens in certain normal circumstances (for short periods of time) let alone if there is any intermittent wireless comms which could let it happen for a long period of time.

                    If you want all radiators controlled in an Evohome system you need an automatic bypass. Personally I think it's worth it and I had an automatic bypass installed so I could control all radiators on our system.
                    Last edited by DBMandrake; 23 September 2020, 09:23 PM.

                    Comment

                    • Mickjohn
                      Automated Home Sr Member
                      • Mar 2015
                      • 68

                      #11
                      Originally posted by DBMandrake View Post
                      I don't understand why you would need to rip up your floor boards to install an automatic bypass valve. They're usually installed within about a metre of the boiler so unless you have a very short pipe run from the boiler before the pipes disappear into the floor installing an ABV shouldn't be a problem.
                      Hi thank you for your reply an earlier post says the automatic by pass valve should be on the other side of the pump from the boiler and my pump is about 7M away from boiler under the floor boards.

                      Mick
                      Last edited by Mickjohn; 24 September 2020, 12:06 PM.

                      Comment

                      • Mickjohn
                        Automated Home Sr Member
                        • Mar 2015
                        • 68

                        #12
                        Originally posted by anniesboy View Post
                        Here is a link to why a bypass is installed.
                        https://www.youtube.com/watch?v=7sp78lBoSPw&t=93s
                        Hi many thanks I think I understand now....

                        Mick

                        Comment

                        • DBMandrake
                          Automated Home Legend
                          • Sep 2014
                          • 2361

                          #13
                          Originally posted by Mickjohn View Post
                          Hi thank you for your reply an earlier post says the automatic by pass valve should be on the other side of the pump from the boiler and my pump is about 7M away from boiler under the floor boards.
                          Ok. Yes it has to go between the output side of the pump and the return line. Strange to have the pump under the floor boards, I've never heard of such a thing...

                          Comment

                          • bruce_miranda
                            Automated Home Legend
                            • Jul 2014
                            • 2307

                            #14
                            Isn't the pump considered a replaceable part of the heating system and thus must be accessible. Installing it under the floorboards has got to be just asking for trouble.

                            Comment

                            • DBMandrake
                              Automated Home Legend
                              • Sep 2014
                              • 2361

                              #15
                              Originally posted by bruce_miranda View Post
                              Isn't the pump considered a replaceable part of the heating system and thus must be accessible. Installing it under the floorboards has got to be just asking for trouble.
                              They also get very hot even when out in the open (flow temperature plus power dissipation of the pump) so I would imagine that having it trapped under floor boards with no way to cool properly would lead to overheating and shortened life.

                              Also, how is the system bled properly if it has to be drained and refilled ? Part of the refilling and bleeding process is to loosen the bleed screw on the front of the pump...

                              Comment

                              Working...
                              X