What would you like to see in evohome? (have your say)

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  • a62vw
    Automated Home Jr Member
    • Mar 2012
    • 15

    Originally posted by victorp1612 View Post
    To echo a request a few pages back : I would like my OpenTherm bridge to allow me to set a max flow temperature on my boiler (a Viessmann) effectively
    I eventually gave up on this request after getting caught in a ping pong match between Viessmann and Honeywell support teams.
    Did you not set the heat curve and shift parameters on the boiler before attaching the Opentherm bridge?
    I work for Resideo. However, any views expressed are mine and not those my employer.

    Comment

    • HenGus
      Automated Home Legend
      • May 2014
      • 1001

      Originally posted by a62vw View Post
      Did you not set the heat curve and shift parameters on the boiler before attaching the Opentherm bridge?
      The ‘issue’ is Honeywell’s fuzzy logic and the demand for maximum flow temperature (as set in the boiler) profile - TMax Set) when a zone is more than c.2C below its target temperature. The other problem is OT’s demand for c.90C flow temperature when re-heating hot water. Not all boilers restrict this demand to TMax Set. If I recall, the Viessmann sits in this category.

      Comment

      • Technomorph
        Automated Home Lurker
        • Aug 2017
        • 6

        Originally posted by DBMandrake View Post
        If you mean having more than one schedule per zone - that doesn't make sense. A zone is a minimum divisible schedule unit. If you really want different temperatures scheduled in different parts of the same zone, make them separate zones. (Of course then you may run into the 12 zone limit, so that leads into your request for more zones)

        If you mean you want the same schedule for HR92's in a zone but to be able to temporarily override one HR92 in the zone without it affecting other HR92's in the same zone - you can already do this by configuring the zone to be a multi-room zone.

        In this mode overrides made at the HR92 itself are not propagated back to the controller or to other HR92's in the zone, so they can be individually overridden then will fall back into line with the next scheduled set point change.

        There are other differences for a multi-room zone though - each HR92 uses it's own internal temperature sensor instead of having a single sensor for the whole zone. It is intended for use when you have a zone spanning multiple rooms such as a "bedrooms" zone so that each room's individual temperature is measured, but you can use this within a single room as well, especially if one end of the room has more heat loss than the other and measuring locally would be an advantage.
        I'm aware of all this. Essentially what I'm suggesting is that a useful feature would be to have sub-zones. For instance, in my master bedroom I have an ensuite and a walk-in wardrobe, each with their own radiator, so three rads in total. Instead of using up separate zones for each, it would be useful to have the option of logically grouping the zones/rooms into Master Bedroom and then being able to control the temp and schedule as a group, or independently. This would keep the interface tidy and provide more granular control. The caveat to this is that I suspect there might be a hardware constraint for the 12 zone limitation which would quickly be exceeded for larger homes. Using two controllers isn't ideal.

        Originally posted by DBMandrake View Post
        Already available. There are already API integrations with IFTTT, Amazon Echo, and many other 3rd party services. With a bit of code its even possible to connect to the API yourself to do your own logging or perform any actions that the smart phone app can perform.
        This is wrong. There is no official public Evohome API. It only seems to be open to approved third parties. There is a thread on this site dedicated to reverse engineering the API. There is an official public API for the Lyric thermostat.
        Last edited by Technomorph; 7 November 2018, 01:02 PM.

        Comment

        • chrisgare
          Automated Home Guru
          • Dec 2013
          • 182

          "Instead of using up separate zones for each, it would be useful to have the option of logically grouping the zones/rooms into Master bedroom"

          Maybe I missed the point here. but this is exactly what I have. My single Master Bedroom zone contains three radiators - two in the bedroom and one in the walk-in dressing room.

          Comment

          • Technomorph
            Automated Home Lurker
            • Aug 2017
            • 6

            Originally posted by chrisgare View Post
            "Instead of using up separate zones for each, it would be useful to have the option of logically grouping the zones/rooms into Master bedroom"

            Maybe I missed the point here. but this is exactly what I have. My single Master Bedroom zone contains three radiators - two in the bedroom and one in the walk-in dressing room.
            Did you read the rest of the sentence...

            ...and then being able to control the temp and schedule as a group, or independently.

            Comment

            • JamboV6
              Automated Home Jr Member
              • Oct 2017
              • 32

              1) support for more zones without needing a 2nd controller. I have 14 rads in my house and it's just a medium size 4 bed house.

              2) fully customisable CUSTOM quick action and not just setting a choice of rooms and 1 temp and time for all. DAY OFF isn't of use because of the way the house is empty or not due to shift work.
              Custom or day off should be effectively an 8th day that can be fully scheduled like any normal day (each room, time and temp) but selectable from quick action.

              3) If I ask alexa to increase a room temp it should increase from the current actual temp and not the scheduled temp. It's obviously set too cold and that's why I want to increase it.

              Comment

              • DBMandrake
                Automated Home Legend
                • Sep 2014
                • 2361

                Originally posted by JamboV6 View Post
                1) support for more zones without needing a 2nd controller. I have 14 rads in my house and it's just a medium size 4 bed house.
                14 radiators, but how many rooms ? There is no limit on the number of HR92's you can have, only the number of zones. So if you have 12 or less rooms but 14 radiators, that's not a problem because you can have multiple radiator controllers per zone that work in tandem.
                3) If I ask alexa to increase a room temp it should increase from the current actual temp and not the scheduled temp. It's obviously set too cold and that's why I want to increase it.
                I can't agree with your logic here.

                Say your set point is 20 degrees but the radiator hasn't been on for long so that the room has only reached 18 degrees so far and is still warming. Under your scheme if you said "increase the temperature" it would actually reduce it from a set point of 20 (the current target) to 19. (one degree above the current measured temperature)

                That doesn't make sense to me at all. An increase should definitely always be relative to the current set point, since you're saying you want it to be hotter than the current target. If the room hasn't yet reached the target then you just need to wait a bit longer, and in that case increasing the set point wouldn't speed that process up anyway.

                If it can't reach the set point in a reasonable time (or at all) due to lack of heat output from the radiator, door left open etc, then asking the set point to be increased also wouldn't help anyway.
                Last edited by DBMandrake; 23 November 2018, 12:09 PM.

                Comment

                • dty
                  Automated Home Ninja
                  • Aug 2016
                  • 489

                  Originally posted by DBMandrake View Post
                  ...in that case increasing the set point wouldn't speed that process up anyway.
                  That's not strictly true. As you know, the demand ramps down as the actual temperature approaches the set point in order to avoid an overshoot. If you increase the set point (especially if you increase it beyond 1.5C above actual temperature) then the valve will open wider, the boiler output will increase and the room will heat faster.

                  I have one room that heats incredibly slowly for various reasons. Like 3-4 hours to add 2C. But Evohome hasn't learned this (or is at the limit of its learned parameter range), so starts ramping down the power waaaaaay too early. To counter this, I often will set that room to 25C, and drop it back to 21C once the temperature is nearly 21C.

                  Comment

                  • dty
                    Automated Home Ninja
                    • Aug 2016
                    • 489

                    Here's an example of the room in question. It's my study. I was working from home this day.

                    You can see at 8:15, I increased the set point from 19C to 21C. The demand increased almost immediately and the temperatures reported by the TRVs started to climb. However, it wasn't until around 12:30 (4 hours later) that the temperature reported by the remote thermostat was almost at 21C. Despite that, the demand started to throttle back after an hour.

                    Screenshot 2018-11-23 at 12.14.07.jpg

                    Comment

                    • JamboV6
                      Automated Home Jr Member
                      • Oct 2017
                      • 32

                      Originally posted by DBMandrake View Post
                      14 radiators, but how many rooms ? There is no limit on the number of HR92's you can have, only the number of zones. So if you have 12 or less rooms but 14 radiators, that's not a problem because you can have multiple radiator controllers per zone that work in tandem.
                      Yes i already have 2 rads bridged for one zone but due to the layout of that room and the environment differences from one end to the other, individual control would be a benefit. The last rad is uncontrolled in the utility and is throttled back slightly.
                      Originally posted by DBMandrake View Post
                      I can't agree with your logic here.

                      Say your set point is 20 degrees but the radiator hasn't been on for long so that the room has only reached 18 degrees so far and is still warming. Under your scheme if you said "increase the temperature" it would actually reduce it from a set point of 20 (the current target) to 19. (one degree above the current measured temperature)

                      That doesn't make sense to me at all. An increase should definitely always be relative to the current set point, since you're saying you want it to be hotter than the current target. If the room hasn't yet reached the target then you just need to wait a bit longer, and in that case increasing the set point wouldn't speed that process up anyway.
                      Considering you commented on my original post regarding this I'm surprised by your comment. I will elaborate for people who did not read my original query regarding this. The set point of a room is 18c, alexa states that the current room temp is 20c, but i dont feel that the room is warm enough for my liking so i ask her to make the room warmer, but instead of increasing the set point to above the 20c that isn't warm enough she only increases the set point to 19c still under the current actual temp.

                      Here is the original post

                      Comment

                      • dty
                        Automated Home Ninja
                        • Aug 2016
                        • 489

                        Originally posted by JamboV6 View Post
                        Yes i already have 2 rads bridged for one zone but due to the layout of that room and the environment differences from one end to the other, individual control would be a benefit.
                        Have you tried setting the zone to a "multi room zone". This enables the HR92s to act independently, although it does mean you can't use a remote thermostat because each HR92 needs its own local idea of the temperature in order to act independently.

                        Comment

                        • Behold81
                          Automated Home Lurker
                          • Nov 2018
                          • 6

                          Support for a Thermal Store rather than DWH Cylinder. More houses are using multiple heat sources with green actions in mind. this means the heating and water could be served from one tank. The control of this depending on the demands should turn on/off the relevant boilers at the right time.

                          Comment

                          • HenGus
                            Automated Home Legend
                            • May 2014
                            • 1001

                            Bearing in mind just how long this thread has been going, I have to wonder whether Honeywell has anything up its sleeve in the way of an updated heating control system that has downwards compatibility and market-leading enhancements? If I recall, people were asking for a WiFi extender over 4 years ago to reduce comms issues: nothing has ever appeared. It is now 4 months since I moved home and I left my 4 year old Evohome behind: apart from the control convenience that Evohome offers, I cannot really say that I am missing it. My stats show that even on a frosty day in Shropshire my 7am to 9.30pm heating cost (at 21C) is c.£2. Any smart heating control is unlikely to have a RoI, and £1000 is a lot to pay for control/convenience.

                            Comment

                            • Behold81
                              Automated Home Lurker
                              • Nov 2018
                              • 6

                              That might be true in some areas but for me I live in the country in a small microclimate and last year I managed to hi -14 degrees on the coldest day. I have to heat my house by fire(back Boiler) or electric boiler. While the back boiler is great and free/cheap energy. over night even a well stacked fire is not much use. or during the day while I am at work. so using electric to heat the house is needed. the more rooms I keep warm the more expensive it would be and full control of that room to room could save me up to £5 a day in heating. payback is quite easy at even half that in 1 year.

                              Comment

                              • HenGus
                                Automated Home Legend
                                • May 2014
                                • 1001

                                Originally posted by Behold81 View Post
                                That might be true in some areas but for me I live in the country in a small microclimate and last year I managed to hi -14 degrees on the coldest day. I have to heat my house by fire(back Boiler) or electric boiler. While the back boiler is great and free/cheap energy. over night even a well stacked fire is not much use. or during the day while I am at work. so using electric to heat the house is needed. the more rooms I keep warm the more expensive it would be and full control of that room to room could save me up to £5 a day in heating. payback is quite easy at even half that in 1 year.
                                If you have costs/savings of that magnitude then I would respectfully suggest that you have other 'problems' that smart heating controls alone will not address. For Mr and Mrs Average, the savings from Evohome are not that great. (ErP claims 8% and BRE conservatively states that zoning might save 1 to 2%. The problem being is that there are almost no definitive scientific studies into the benefits of smart heating controls).

                                Looking back at the daily stats that I kept, I saved more by adding a new condensing boiler to an existing Evohome system, than I did by adding Evohome to an existing system with a 12 year old non-condensing boiler some 3 years earlier. Evohome is a great and a generally reliable - but somewhat dated - product. That is just my opinion based on 4 years of use - through 2 controller iterations - and a couple of firmware updates.

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