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Central Heating - control with timer and thermostat at different times

Discussion in 'Plumbing and Central Heating' started by desig, 22 Dec 2020.

  1. desig

    desig

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    Hi all
    I've read around a few other threads, but I don't think this exact question has been asked before... (and apologies if it has! In which case please direct me to it)

    Boiler: Greenstar 38 CDi
    Thermostat: Honeywell DTS92E1020 wireless thermostat
    Receiver: I don't remember exactly, but I think it's the BDR91 relay that came with the thermostat?

    We've been using this boiler and thermostat combination for 4 years with no issues. The boiler has a timer function on it too, however we don't normally use it (set to always on, and control heating from the thermostat). The timer is only used to set the heating to come on only on certain days in winter where we have been away and want to come back to a warm house.

    It's been a while since I've used that function, but I believe the timer is only turning on the heating if the thermostat is also set to a temperature where it should turn on. i.e. if I set the thermostat temperature too low, then the timer alone won't fire up the boiler. Or the thermostat alone won't turn on the heat, as the timer has to also be on at the same time (either always on, or timed on).

    We keep the thermostat in the little cradle it came with, and usually move it around the house. During the day it's in the large open plan living room, and in the night it's in our kids bedroom, to make sure it doesn't drop below 18 degrees in the night.

    We want to start controlling the heating a bit smarter (but not necessarily with a "smart" tool, unless that is what is required). Is there a way for us to be able to make the heating switch on at say 06:30 or 7am, even if the thermostat is still in the kids room and the room temperature is still above the thermostat target temp of 18 degrees?

    I had a quick look and it seems like the Honeywell CM927 could achieve that with the heating program, where it splits the day into 6 periods. It looks like the CM927 could also be compatible with the receiver we already have connected to the boiler.

    Would that be a good thermostat to use to meet our needs? I don't mind getting something else if it also means replacing the receiver connected to the boiler.


    As an additional question, are there any recommendations on what could meet our needs, but also have "smart" or remote capabilities, should we ever decide to need the ability to control the heating remotely (like using an App to turn on the heating when on the way home from a weekend away, not that is likely any time soon!)

    I am quite security conscientious though, so would only prefer to have "smart" capability if I can also control through my router what can connect to the smart heating.


    Thanks
    desig
     
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  3. ianmcd

    ianmcd

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    get a hive single channel thermostat, it has time and temp control and can be controlled by a phone app
     
  4. muggles

    muggles

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    Short answer is no - if the thermostat is in a room which is above the target temperature, the heating won't come on, regardless of what thermostat you have. You could get a single zone smart stat such as Hive as Ian suggests, then use your app to increase the target temp if desired. You could get your system rebalanced so that every room heats up at the same rate, thereby eliminating the problem of your children's room being warmer than the rest of the house. You could also convert to a full smart system which would allow control of individual radiators or groups of radiators - that way, the children's bedroom could stay at 18 while other rooms are set to different temperatures.
     
  5. lloyda

    lloyda

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    The BDR91 relay can bind with up to four thermostats/timers. So you could add a CM927, and keep the existing DTS92 thermostat which would effectively operate as an override if the room it is in gets too cold.
     
  6. Lower

    Lower

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    Depends on how complex you want to make it and what temperature you want to achieve at different times.

    With a nest thermostat or similar, you can set the target temperature to be different at different times of the day or night.

    For example, ours is set to keep the house at 20 degrees from 7am through to 6pm, 21 degrees from 6pm-10.30pm and then 16 degrees from 10.30pm-7am.

    If you really want different temperatures in different rooms of the house you'd need different zones on your heating system which would probably mean a partial replumb, or programmable TRV's on you radiators with a compatible thermostat to enable you to set different temperatures in different rooms at different times.

    With either option your timer becomes redundant because your thermostat daily temperature schedule tells the heating when it needs to be on.
     
  7. ericmark

    ericmark

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    You can have as many thermostats as you want in parallel, so if any calls for heat, the boiler will switch on.

    Also you can stop any room over heating using a thermostatic radiator valve (TRV).

    So between the two you can get some where near what you want.

    Hive has an odd method, the wall thermostat sets the minimum temperature in that room, however the TRV heads can send a signal to the wall thermal which will over ride the wall thermostat for 1/2 hour.

    There are many more that link the TRV head to some hub of some kind.
     
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