Results 1 to 5 of 5

Thread: Controlling electric heating and comfort pump

  1. #1
    Automated Home Lurker
    Join Date
    Dec 2017
    Posts
    4

    Default Controlling electric heating and comfort pump

    Anyone an expert on the new electric zone in the new firmware?

    I have two things I want to control:-

    1) My Electric UFH in my bathroom. <1KW. Currently switched by a sensor on the floor so all I need from Evohome is an on/off. Can I bind a zone without a Evohome linked temperature sensor? If not, do you think Honeywell will release a compatible floor sensor?

    2) My comfort hot water pump. It's currently controlled by a timer. I'd like to replace this with a BDR91 and no temp. sensor.


    Cheers

    Toby

  2. #2
    Automated Home Legend
    Join Date
    Sep 2014
    Location
    Scotland
    Posts
    2,101

    Default

    Quote Originally Posted by tobybuk View Post
    Anyone an expert on the new electric zone in the new firmware?

    I have two things I want to control:-

    1) My Electric UFH in my bathroom. <1KW. Currently switched by a sensor on the floor so all I need from Evohome is an on/off. Can I bind a zone without a Evohome linked temperature sensor? If not, do you think Honeywell will release a compatible floor sensor?
    The Evohome doesn't support zones without a temperature sensor. I'm not sure why you would want to though ?

    Underfloor heating would typically use two temperature sensors - one measuring the temperature of the element in the floor to regulate that and ensure it doesn't go over temperature (which you already have) and a second one measuring the air temperature of the room so that the temperature of the floor is throttled back when the room temperature set point is reached.

    This is analogous to a boiler having a flow temperature thermostat to regulate the maximum flow temperature in addition to a room having an air temperature sensor to have overall control of the temperature in the room.

    Unless your underfloor heating is so weak that it can't heat the room at all and is only there to make your feet feel warm, you still need a room temperature sensor, and with Evohome you definitely need a room temperature sensor of some kind.
    2) My comfort hot water pump. It's currently controlled by a timer. I'd like to replace this with a BDR91 and no temp. sensor.
    I'm not even sure what a "comfort hot water pump" is ? But again, all zones in Evohome have to have a temperature sensor. It doesn't have an on off mode for zones.
    Last edited by DBMandrake; 22nd January 2018 at 08:58 AM.

  3. #3
    Automated Home Lurker
    Join Date
    Dec 2017
    Posts
    4

    Default

    Thanks for replying.

    The comfort pump is there so when you turn a hot water tap on you get almost instant hot water. It needs a hot water circuit in the house that's on a loop, with a special pump that slowly pumps hot water around the loop. Then each tap is fed from a short drop from the loop. Obviously this does waste a bit of heat so you put the pump on a timer and schedule it for peak times of the day. If Evohome could switch without a temp. sensor then it could be used to control the pump.

    As for the UFH its there simply to keep the floor warm. Problem is the rad in the bathroom gets the room nice and warm quickly. If I ran the UFH off the rad sensor then it wouldn't have enough time to get the floor warm (its stone) before the room temp. was satisfied. I guess for this one I'll have to wait until a UFH temp. sensor is released.

    All my issues could be solved if we could have an on/off heating zone.

    Again, thanks for the reply.

  4. #4
    Automated Home Sr Member
    Join Date
    Oct 2017
    Location
    France & UK
    Posts
    74

    Default

    Quote Originally Posted by tobybuk View Post
    Thanks for replying.

    The comfort pump is there so when you turn a hot water tap on you get almost instant hot water. It needs a hot water circuit in the house that's on a loop, with a special pump that slowly pumps hot water around the loop. Then each tap is fed from a short drop from the loop. Obviously this does waste a bit of heat so you put the pump on a timer and schedule it for peak times of the day. If Evohome could switch without a temp. sensor then it could be used to control the pump.

    As for the UFH its there simply to keep the floor warm. Problem is the rad in the bathroom gets the room nice and warm quickly. If I ran the UFH off the rad sensor then it wouldn't have enough time to get the floor warm (its stone) before the room temp. was satisfied. I guess for this one I'll have to wait until a UFH temp. sensor is released.

    All my issues could be solved if we could have an on/off heating zone.

    Again, thanks for the reply.
    All you need is the cheapest Evohome room sensor with the target temperature for that zone set to a high temperature (say 25deg) That way irrespective of the actual room temperature, the controller will bring the ufh electric heating at the times required. We have a bathroom electic floor ufh with its own controller (programmer and thermostat) and floor temperature sensor. If I was adding evohome controller to this for scheduling I would simply use Evohome controller to switch the power to built in ufh controller using a BDR91 at the required times . This way the floor would simply come on at the required time and its temperature would be adjusted by its own controller.

    Of course the only advantage of this is remote control of the ufh (as normally you could just use the built in ufh controller) plus of course you get to see the actual bathroom temperature on the Evohome controller. In our case it could be useful as that bathroom is only used occasionally so maybe I'll seek out a BDR91+room sensor package
    Last edited by rvb99; 22nd January 2018 at 01:29 PM.

  5. #5
    Automated Home Jr Member
    Join Date
    Nov 2015
    Posts
    22

    Default

    I've just posted my recent fun with evohome and electric underfloor heating here: https://www.automatedhome.co.uk/vbul...ll=1#post39450

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •