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Thread: Switching Off a ZONE?

  1. #1
    Automated Home Jr Member
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    Default Switching Off a ZONE?

    Hi all

    Today I installed 4 HR92UK to my system. Prior to this I only had the Evohome controller and the wireless receiver on the boiler.

    So, I created 2 zones:

    Shop
    Bedroom

    Each zone has 2 HR92UK radiator control valves.

    Is it possible to switch one zone off or is this achieved by reducing the temperature?

    Many thanks

    John

  2. #2
    Automated Home Legend paulockenden's Avatar
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    After a while with Evohome you start to stop thinking in a binary way like that. Rather than turning a zone off, you set it to a temperature that feels comfortable. In an empty room that might be 13-15 degrees.

    P. (Who like you, was a "how do I switch this off" person at first).

  3. #3
    Automated Home Legend top brake's Avatar
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    Best way is to put it on a permanent override at a moderate temp say 14 deg. You don't want it too cold or it will leech heat from other zones and the contents will go musty.

  4. #4
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    Quote Originally Posted by datasafe View Post
    Is it possible to switch one zone off or is this achieved by reducing the temperature?
    Yes.

    The lowest temperature you can set is 5 degrees, this is the closest you will get to turning a zone off. The radiator will remain off unless the the room drops to 5 degrees, then it will come on to prevent the room going below 5 degrees. This is to provide frost protection.

    Keep in mind that when you use the "Off" quick action all it really does is sets all zones to 5 degrees to ensure that frost protection is maintained. If any rooms go below 5 degrees in "Off" mode the boiler and respective radiators will still come back on to prevent freezing.

    I schedule all rooms in the house except the bedroom to 5 degrees at night, and all rooms to 5 degrees during the day when the house is empty.

    As top brake has said, a permanent 24/7 override of 5 degrees is probably not a good idea because the room will get musty and damp and the cold walls from that room will leech heat from other rooms, so 10-15 is more reasonable for a permanent set back, but IMHO 5 is fine if the room is scheduled to warm up at other times of the day.

  5. #5
    Automated Home Legend top brake's Avatar
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    OFF quick action is only intended for summer use really. Overnight setback typically 3-5 degrees cooler than daytime comfort levels. If you let the building thermal mass cool down too much you will have an uncomfortable house with cold walls.

  6. #6
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    WoW!

    Thank you very much for all the replies - very helpful

    Regards

    John

  7. #7
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    Quote Originally Posted by paulockenden View Post
    After a while with Evohome you start to stop thinking in a binary way like that. Rather than turning a zone off, you set it to a temperature that feels comfortable. In an empty room that might be 13-15 degrees.

    P. (Who like you, was a "how do I switch this off" person at first).
    I'm still yet to convince my other half of this

    She's one of those people that see heating as on or off, we've had numerous discussions of "why is the heating on" when the room is a bit warmer than usual due to a warm day for me to point out that yes it is "on" but because the rooms are all above their set points the radiators are actually cold and the boiler is off... Turning the heating off does nothing further in this case as the boiler was already off anyway, then you need to remember to turn it back on again when the cold evening sets in rather than having it just automatically come on when needed.

    Likewise with rooms like the bathroom and kitchen - when they are actively in use they are scheduled to about 20 degrees (24 for shower time in the bathroom) but during times of the day when the house is occupied but outside the normal use time of those two rooms I schedule them back to 16 degrees rather than 5. ("Off") In warmer weather this 4 degree set back is enough that when the schedule changes from 24/20 to 16 the radiators go off and stay off until bedtime as the temperature doesn't fall to the set point, at which time they are scheduled back further to 5 degrees to ensure they don't come on in the night.

    However in very cold weather the radiators in those two rooms will go off for two or three hours then come back on gently when the rooms fall to 16 degrees and hold them there - my reasoning for this is that you don't really want your bathroom falling down to 10-12 degrees during the day/early evening when you might want to make a pit stop! By trial and error I found about 16 was the lowest comfortable temperature in that room for that use, but without having the room warmer than it needs to be in a mostly unoccupied room.

    Similarly in the kitchen the morning schedule is 20 degrees so the room is nice and warm, then it drops back to 16 during the day while someone is in, then for dinner time it goes back up to 18. I chose 18 instead of 20 because if you let the room warm up to 20 before you start cooking heat from the oven etc can end up leaving the room well over 22-24 degrees because it takes time for the rise to be detected and the radiator to go off. Whereas if you start at 18 as soon as the oven starts warming the room past 18 the radiator goes off and the oven will not overheat the room as much past 20. (This would work better with a wall mounted thermostat though - I find the oven heat takes quite a while to find its way down to the corner where the HR92 is, which is between two cabinets under a bench top! Not the best location to measure temperature...

    After dinner time the kitchen drops back to 16 - you don't really want to be tidying up the kitchen in 10-12 degree temperatures before bed.

    After a while you start thinking in terms of temperature schedules rather than on/off schedules. Not only can you schedule every room independently, it's a temperature schedule not an on/off schedule. The only times I have zones truly off (5 degrees) is when the house is unoccupied or rooms other than the bedrooms in the night.
    Last edited by DBMandrake; 10th October 2016 at 02:14 PM.

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