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Thread: Independent control of heating for 5 rooms.

  1. #1
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    Default Independent control of heating for 5 rooms.

    I am looking at a property to rent out on “room by room” bases (HMO), so wish to allow each tenant to control the heating in their room. I will have a gas boiler and am happy to have a buffer tank if needed.

    • I need the in room controls to be simple for the tenants to use.
    • I need to be able to place limited on the max temperature a room can be set to.
    • I wish the heating to be turned off when the window is open
    • As tenants will have different bedtimes, I would like each tenant to be able to control the timing of their own heating.
    • Ideally I would like some idea of how much heat each room is taking.
    • I want low running costs and capital costs.


    The “Smart” TRV I have looked at are not easy to program the timing on and can’t have the max temperature locked while still allowing timings to be changed.

    What options should I be looking at?

  2. #2
    Automated Home Guru MichaelD's Avatar
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    You've just described the situation that the honeywell CM-zone system was designed to suit. Apart from providing knowledge on the running costs.

    HR80s on each room's radiators, and a CM67z in each room will allow easy local control, and limit the maximum temperature.

    But, if someone googes the system and is stupid enough to want the room heated to 28 degrees, then they will be able to adjust any upper limits you set.

  3. #3
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    You could achieve this with an fs20 based system, but you would have to write your own module in a free app called Fhem.

    The only way I can see of setting the top temperature would be to write a module that when the users selects a temp greater than X, Fhem would tell the room to go back down to Y

    So the user, may get the benefit of the higher temperature for a short period of time, before the room unit is told to reset itself to the old max temp.

    You could then use the logs in fhem to see the rad open % to see which rooms were calling for heat when...

    Fon

  4. #4
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    The Conrad (ELV) system using FHT8R zone controllers will do most of what you want. It won't limit the max temperature in each zone (do that by setting the water temperatuire using a weather compensator). It won't calculate costs. There is a version that has window sensors. But it will provide individual room programmer and temperature functions.

    It will lower running costs but requires an investment up front.

  5. #5
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    The Conrad (ELV) system using FHT8R zone controllers post above is the fs20 system that I also posted , and WILL do what you want if you use FHEM

    Fon

  6. #6
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    Be careful here. The Conrad/ELV documentation is unclear and misleading. The FHT8R controllers don't have a receive capability and can't be controlled from another device. For that you need the FHT80b controllers, which look the same in the illustrations but are in fact larger and probably more expensive. These can be controlled directly by the FHZ-1000 Wireless Control Centre, which you would retain control of. They all use the same FTS800C radiator actuator. But the FHZ-1000 may not give you the individual temperature limits that you want, unless you have one per room, in which case costs will be very high and not worth the investment. Download the manual from Conrad and read it very carefully. They all use the FS80 protocol. But the protocol does not determine what the equipment can do, it is only a transmission format. All this is off-the-shelf gear. It is shipped from Germany even if bought from the UK web site. There is no single document that explains what parts are compatible with which others. Conrad have only a 14-day return window.

    The point about a weather compensator is that it lowers the radiator temperatures as it warms up outside. This may be the biggest energy saving opportunity of all.

    FHEM may be useful but you will have to install a linux server, attach some interface hardware, and then install, program and maintain the system.

  7. #7
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    What Geoff said. I have a number of the FHT8R units, acquired a couple of months ago, but I only just got around to getting FHEM up and running, only to find that each unit only reports valve actuator value, and not measured temperature, and I can't send any commands to them.

    Slightly annoyed at myself, tbh.

    Considering swapping out the FHT8Rs for some of the FHT80 units, but the other option is to cut my losses and sell the CUL dongle I'm using for FHEM, and stick with just the individual room controls and the boiler interlock that is already proving successful.

  8. #8
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    Just make sure you buy the fht80 units for each room. You will also need an fht8r for each rad. Then you will know the temperature, and also be able to set it for each room.

    You can get these very cheaply on ebay.de but some germans wont send them to the uk.

    Since I used these in 6 rooms in my house, along with Fhem. I have reduced my gas bills by 40% in the winter, and 20% in the summer.

    Fon

  9. #9
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    Thanks for all the helpful answers,

    I have looked at the Conrad documentation and for some reason it seems harder for the user to set the temperature and times then on the HP CM67z, also the Conrad does not seem to look nice on a wall.

    There don’t seem to be a nice way to gather the “call for heat” from the HP setup, as the HP boiler controller seems to be limited to only 4 CM67z.

    Both the Conrad and HP system has at least 2 sets of batteries that need changing in each room and the possibility of wireless reception issues. As gaining access to a rental room can be hard, I rather avoid these problems if possible.
    In both cases someone can just remove the smart TRV to defeat the system.

    I have been having some thoughts of my own.

    • Use a UFH manifold as it makes it easy to balance the system and allows a single room to be isolated when work is being done on that room without draining down the system.
    • Use a Danfoss Randall TP5000M Si Thermostat/Timer in each room wired back to a 4 wire activator on the manifold. (Lots of other options for thermostat, no vendor lock in, THERMOPLUS AS1 may be a nice option)
    • Use the switch in the activators to control the CH pump/boiler, (if not using a buffer tank and a “smart” CH pump)
    • Connect an Hours Run Meter to each Room Thermostat to recall for how long each room calls for heat


    Comments please….

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