Evohome setup to incorporate a thermal store unit

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts
  • dafydd
    Automated Home Jr Member
    • Mar 2020
    • 13

    Evohome setup to incorporate a thermal store unit

    Hi, I have an existing thermal store system, and I'm in the process of adding Evohome controls. My plumbing knowledge is next to nil!!
    I can't get my elderly head around what and how Evohome is going to have to control with this thermal store system. All the instructions deal with either combi or conventional systems! The thermal store takes mains pressure water in through a coil and directly out to the taps. The water around the coil is kept at around 70 - 80 o from what I've read. The central heating water comes from this surrounding water I take it?
    I'd appreciate any help or advice.
    cheers!!
    Dafydd
  • mtmcgavock
    Automated Home Legend
    • Mar 2017
    • 507

    #2
    Originally posted by dafydd View Post
    Hi, I have an existing thermal store system, and I'm in the process of adding Evohome controls. My plumbing knowledge is next to nil!!
    I can't get my elderly head around what and how Evohome is going to have to control with this thermal store system. All the instructions deal with either combi or conventional systems! The thermal store takes mains pressure water in through a coil and directly out to the taps. The water around the coil is kept at around 70 - 80 o from what I've read. The central heating water comes from this surrounding water I take it?
    I'd appreciate any help or advice.
    cheers!!
    Dafydd
    Simple answer is Evohome won't work with Thermal Stores.

    Comment

    • kevinsmart
      Automated Home Ninja
      • Sep 2018
      • 257

      #3
      Originally posted by mtmcgavock View Post
      Simple answer is Evohome won't work with Thermal Stores.
      Not true according to other posts on this forum if you do a search.

      Comment

      • mtmcgavock
        Automated Home Legend
        • Mar 2017
        • 507

        #4
        You can make it work of a basic fashion but not how it should, and tbh won’t be very efficient.

        Aren’t you thinking of Unvented cylinders? As which there’s a difference between a thermal store and Stored Hot Water.

        Comment

        • EvoPhil
          Automated Home Jr Member
          • May 2019
          • 12

          #6
          Originally posted by mtmcgavock View Post
          Simple answer is Evohome won't work with Thermal Stores.
          Whilst I've not got Evohome, I've got Drayton Wiser, I'm sure the principle is the same. I have a thermal store (fed by biomass which Drayton Wiser does not officially support) and my Wiser system simply switches my circulation pump on and off using the same 'wall mounted thermostat' wires that were there before I got a smart system. I have 2 heating zones with about 5 TRVs on each and a separate DHW circuit which runs independently of the Wiser system.

          Comment

          • paulockenden
            Automated Home Legend
            • Apr 2015
            • 1719

            #7
            I have a thermal store but it's on the DHW feel to my combi, rather than on the heating side. It mops up solar export and means that I use no/less gas when having a shower or a bath.

            I don't let Evohome anywhere near it! ;-)

            Comment

            • G4RHL
              Automated Home Legend
              • Jan 2015
              • 1580

              #8
              It’s some months back since this subject was raised but my interest in a thermal store has been aroused. I wonder if any of the professionals on this site can add anything about the use of Thermal Stores with an Evohome system. Presumably one does not use Evohome to regulate DHW temperature for obvious reasons but you let it control itself according to demand, but does the CH otherwise work as normal with zones calling for heat as I have now? Thus making the DHW aspect of the Control Panel redundant?

              Comment

              • EvoPhil
                Automated Home Jr Member
                • May 2019
                • 12

                #9
                I'm no professional, but have installed my Wiser system myself - even against the advice of Drayton, so please take my advice with a pinch of salt. Assuming the evohome system signals like the Wiser system, then I'm sure it should work. My system prior to changing to Wiser, had (at one point) a simple open/closed set of contacts that would allow the circulatory pump to run. All I did was to take the zero volt contacts from Wiser and use them to switch the pump, rather than the 'old' simple wall thermostat, that also had a simple no-volt open/closed set of contacts. The Wiser hub (has the contacts) has either a 240 set of contacts or a zero volt set of contacts. Due to the number of TRVs I was going to need, I had to use 2 hubs, so got the basic ones (with zero volt contacts) and use 2 of them, via 2 logins to their app. My DHW is controlled by my boiler (as before) and I've not felt the need to integrate it into the boiler, but one other reason why not is because if my boiler gets too hot, it can dump excess heat into the DHW and I doubt the Wiser system could accommodate this (a safety feature).

                How is you system 'switched' currently? Does it use a 'dumb' thermostat on the wall that simply switches a set of contacts or something else?

                Comment

                • G4RHL
                  Automated Home Legend
                  • Jan 2015
                  • 1580

                  #10
                  My current system is an old gas boiler for heating and DMH. Working through a three-way valve. Evohome controls it all, sending messages when heat is needed or not. DHW is similarly set up with a strapped on thermostat talking to its base which in turn talks to its own relay. All works, no real problems. Pleased with it.

                  Ahead though is a growing need to change the boiler. It’s getting old. A vented Thermal Store appeals because it gives DHW at mains pressure. No pumps for the showers as I have at present. Also they have some future proofing in that they can be used with alternative power sources. It also means I can get rid of the tanks in the loft and create more space for stuff - others will call it sh.t but then what they call “stuff” I would call sh.t.

                  My current thinking is to install the DHW internal thermostat that works with Evohome (if that is possible) and possibly with time controls set up when it is to operate. With some Thermal Stores it seems you can. But perhaps better ignored and let the boiler just fire up when it senses the store needs a top up. I don’t know if that will work or prove expensive to run and am looking into that. Our DHW is only heated for 30 minutes in the morning and 30 in the evening.

                  Comment

                  • mtmcgavock
                    Automated Home Legend
                    • Mar 2017
                    • 507

                    #11
                    Originally posted by G4RHL View Post
                    My current system is an old gas boiler for heating and DMH. Working through a three-way valve. Evohome controls it all, sending messages when heat is needed or not. DHW is similarly set up with a strapped on thermostat talking to its base which in turn talks to its own relay. All works, no real problems. Pleased with it.

                    Ahead though is a growing need to change the boiler. It’s getting old. A vented Thermal Store appeals because it gives DHW at mains pressure. No pumps for the showers as I have at present. Also they have some future proofing in that they can be used with alternative power sources. It also means I can get rid of the tanks in the loft and create more space for stuff - others will call it sh.t but then what they call “stuff” I would call sh.t.

                    My current thinking is to install the DHW internal thermostat that works with Evohome (if that is possible) and possibly with time controls set up when it is to operate. With some Thermal Stores it seems you can. But perhaps better ignored and let the boiler just fire up when it senses the store needs a top up. I don’t know if that will work or prove expensive to run and am looking into that. Our DHW is only heated for 30 minutes in the morning and 30 in the evening.
                    You'd be better with an Unvented HW cylinder than a thermal store, especially if you've only got one heat source. You'd have to heat the store to a high temperature, for longer periods than you do now. An Unvented cylinder you could probably get away with what you heat it now.

                    Comment

                    • G4RHL
                      Automated Home Legend
                      • Jan 2015
                      • 1580

                      #12
                      Installing an unvented cylinder may not be practical as I am advised radical changes to the incoming cold water feed are needed but none are needed with a vented cylinder it being a simpler alternative. I note that Worcester Bosch have stopped making unvented cylinders.

                      Comment

                      • mtmcgavock
                        Automated Home Legend
                        • Mar 2017
                        • 507

                        #13
                        Originally posted by G4RHL View Post
                        Installing an unvented cylinder may not be practical as I am advised radical changes to the incoming cold water feed are needed but none are needed with a vented cylinder it being a simpler alternative. I note that Worcester Bosch have stopped making unvented cylinders.
                        Isn’t going to be any different for a thermal store? It’s still mains pressure for the HW...

                        They’re just a bad idea IMO, ripped so many out over the years. I’d have a combi before a thermal store.

                        Comment

                        • G4RHL
                          Automated Home Legend
                          • Jan 2015
                          • 1580

                          #14
                          Yes it is, different that is. I understand unvented needs the cold water main taking straight to it and that means work on the cold water taps. Not practical in my case.The vented does not have this problem. On the latter I am100% certain but not so sure on the former. As for viability it seems they have come a long way in the last few years and there are plenty of them being made. I first came across them with a friend who had a vented thermal store. He inherited it when he bought his property but found it excellent. More recent articles about them are much more positive than ones of 10 years ago. The unvented is not cheap to install and has cost issues. My mind is not made up though I am just looking at all permutations including electric - a dry system.

                          Comment

                          • mtmcgavock
                            Automated Home Legend
                            • Mar 2017
                            • 507

                            #15
                            Originally posted by G4RHL View Post
                            Yes it is, different that is. I understand unvented needs the cold water main taking straight to it and that means work on the cold water taps. Not practical in my case.The vented does not have this problem. On the latter I am100% certain but not so sure on the former. As for viability it seems they have come a long way in the last few years and there are plenty of them being made. I first came across them with a friend who had a vented thermal store. He inherited it when he bought his property but found it excellent. More recent articles about them are much more positive than ones of 10 years ago. The unvented is not cheap to install and has cost issues. My mind is not made up though I am just looking at all permutations including electric - a dry system.
                            The vented section is the store only, the HW is supplied by mains pressure that runs through a coil.

                            Only want round it would be to fit a new vented cylinder like I assume you have now.

                            Comment

                            Working...
                            X