Replacement Thermostat

Discussion in 'Electricians' Talk' started by zimmi, Feb 2, 2022.

  1. zimmi

    zimmi New Member

    Good morning all,

    I am wanting to replace my current old outdated thermostats with something more modern but have no idea what products would be suitable replacements as I have zero knowledge with in the field.

    I have ESWA ceiling heating, with individual room thermostat controls in each room plus a Horstmann H527 that seems to control them all.

    Would anyone be able to point me in the right direction? I, in the perfect world, would like to get something similar to Hive/Nest but if this is not possible, just something a little more 2022 that what I currently have.

    Any help would be amazing!

    Thanks Per-room-thermostats.jpg IMG_3063.JPG
     
  2. Tony Goddard

    Tony Goddard Screwfix Select

    The thermostat unit would have been made by ACL for the ceiling heating firm, it has the same housing as a regular ACL stat of the 80's / 90's, however it may be a special product (ie designed specially to work with the ceiling heating system)

    I would advocate carefully (with power off) dismantling the stat and post some pics of the connections on the back, it may be just a simple thermostat switching the current to the ceiling or it may have a probe embedded somewhere up there much as underfloor systems have.

    If it is just a regular thermostat, then there are many possible options, if it is a specialist control it may still be possible to use a hive/nest but the current stat may have to remain in place too.
     
  3. Tony Goddard

    Tony Goddard Screwfix Select

    Just had a watch of this video, explains how it works



    it appears there should be a temperature limitation sensor wired to the thermostat, thats an important safety feature so has to remain - do you have the thermostats in every room?
     
  4. zimmi

    zimmi New Member

    Thanks for the replies, I was going to take the panel off and take photos of the wiring but need to wait for after work hours to turn off the power.

    Yes, I have those small square thermostats with the dials in each room.
     
  5. Bazza

    Bazza Screwfix Select

    Many modern thermostats are designed for low current applications. Your ceiling heating may need more amps than the regular stats can handle.
    Will be able to tell more when we can see inside the existing thermostat.

    What functions do you want to add? Remote temperature adjustment? Wi-Fi controls?
    Are you happy with the two zone controller, or do you want something else? What functions needed there?
     
  6. zimmi

    zimmi New Member

    good morning, i managed to take off the zone control box. pls see images attached. thanks IMG_3083.JPG IMG_3082.JPG
     
  7. Bazza

    Bazza Screwfix Select

    Fine. The contacts are rated at 3amp, so most two channel programmers can replace the zone control box. I’ll ask again
    next (again) need to see inside one of the thermostats for information on the amp requirements there.
     
  8. MGW

    MGW Screwfix Select

    You will note the thermostat has only numbers, it seems likely the ceiling panels use inferred, this does not heat air directly but heats items in the room, then the items heat the air, the colour and texture of the thermostat will make a huge difference if in line of sight to the ceiling.

    It seems odd to have only two panels, the problem with inferred is the effect is immediate, both when switching on and when switching off. So the standard inferred heater normally has many elements and more or less are switched on.

    This was typical upload_2022-2-7_23-6-9.png with 4 x 400 watt bars so it could be increased or decreased rather than full on/off. Be it on the floor wall or ceiling the same applies switching the whole on/off does not really work, as soon as switched off one would feel cold.

    Even a triple glazed window will not stop the heat passing through it, so have to use something like
    or ensure curtains are always closed.

    In the main inferred is used as a part of a complete system, we look at eco and comfort temperatures, so for example 17ºC air temperature with a PIR that turns on the inferred so as one walks into the room it feels like 20ºC.

    I had a similar system in my old house, the room air heated to 18ºC and when we walked into the room we manually switched on the inferred heater and lights, this made it feel like 20ºC. In our case the heater and light was combined and was better known as 6 x 60 watt tungsten bulbs. When the bulbs were swapped for light only type, the thermostat had to be changed for a programmable type so air temperature raised by 2ºC in the evening.

    I know the Nest thermostat has a built in PIR to swap from eco to comfort when some one is at home, it can also use location of mobile phone, but I have never looked to see if the thermostat can be programmed for use with inferred heating panels.

    The fact it changed colour if on or off may either assist or completely mess up the system. This is rather a special system, if I was asked to do the job, it would be sub contracted to an expert, only seen it used in places like a church, where only want heat for an hour or so, or garage where doors are opened to let vehicles in and out, so don't want to heat the air. Only place seen used in the domestic is bathroom where again heat only needed for a short time.

    3 amp does not seem enough to heat a room, around 750 watt, so I suspect there is some thing your unaware of, a set of relays for example.
     
  9. zimmi

    zimmi New Member

    thank you everyone for your replies.

    Here are pictures of the Thermostats themselves... and some info on the ESWA ceiling heaters IMG_3097.JPG IMG_3096.JPG IMG_3095.JPG IMG_3094.jpg IMG_3093.jpg
     
  10. zimmi

    zimmi New Member

    in reply to what I would like:

    In a perfect world, if I could replace all the individual thermostats with 1 central device that would allow me to adjust each room via an app... that would be amazing. I'm not overly worried about 'smart' thermostats that learn your habits etc, but being able to turn them on/off/set temp in 1 place would be ideal. If this is not possible, just being able to replace the hideous dated thermostats with something more modern/digital would be great.
     
  11. Bazza

    Bazza Screwfix Select

    The existing thermostat is rated at 16AMP. My guess is that high current handling is because the heating load is being switched by the stat.
    Unless: do you hear a loud clunk from somewhere, when the heating switches on and off?
     
  12. zimmi

    zimmi New Member

    Yes, the larger zone controller device, when it switches on there is a loud clunk sound
     
  13. zimmi

    zimmi New Member

    Does anyone have any final recommendation? Please and thank you :)
     
  14. Teki

    Teki Screwfix Select

    If all the wiring goes back to a central wiring centre, then you could consider a Heatmiser system:

    https://www.heatmiser.com/en/

    As you don't seem to have a neutral at the thermostat location, you'd need a battery powered digital thermostat capable of switching up 16A.
     
  15. SIRJOHN19

    SIRJOHN19 Active Member

    The neutral is the bottom terminal.
    Disconnected dozens of these ceiling heating systems over time.
    A new bungalow estate had them all fitted and all of them changed to storage heating within 2 years!
    Judge for yourselves.
     
    Teki likes this.
  16. Teki

    Teki Screwfix Select

  17. CeilingFan

    CeilingFan New Member

    @zimmi did you find a solution? I have the exact same issue (we might even live in the same place looking at your pictures).

    @Teki I'm trying to find a smart wifi thermostat but also one with a remote sensor, as due to removing a wall the original is no longer in the optimal place. The one you posted above, would that work based on my wiring (attached)? It doesn't have the remote part but at least it's a start. Cheers!

    Current thermostat is rated at 16A.
     

    Attached Files:

  18. Teki

    Teki Screwfix Select

    Here are some options with an external sensor connection:

    https://www.danfoss.com/en-gb/produ...ting/electric-underfloor-heating-thermostats/

    https://www.amazon.co.uk/Underfloor-Thermostat-Temperature-Controller-Proframmable/dp/B096ZQR93Q

    https://www.amazon.co.uk/Underfloor-Heating-Programmable-Electric-Thermostat/dp/B07C15QQY3
     
  19. Bazza

    Bazza Screwfix Select

    @zimmi @CeilingFan
    I do not want to dis the post from @Teki , and it is not easy to evaluate a situation and provide correct advice from the other side of a keyboard, across the internet.
    Also, we now have two slightly separate requirements, so hijacking the original topic isn't helpful.
    So bear that in mind. Here is my take on possible way forward.

    ROOM THERMOSTAT CHOICES
    Referring to Teki's post with links to thermostats with external sensors. You DO NOT require an external sensor. The thermostats need to detect the temperature of the AIR in the room (like the existing ones). External sensors are used to control the temperature in (typically) under floor heating (UFH) systems. In your case the heat for the room is coming from the ceiling!
    EDIT: some thermostats do have an option for remote air/room sensor.
    eg https://www.heatmiser.com/en/wireless-sensors/
    @CeilingFan If your wall has moved, perhaps you should extend the wiring and move the thermostat to a more optimal position?

    One thing that UFH thermostats usually have is the ability to switch high current loads. So one of Teki's suggestions might be suitable, but you MUST MUST check that the thermostat is rated at a high enough current (the existing ones are 16amp) and the thermostat must have the ability to detect the room temperature (often a menu option).

    Then you need to decide how you want to control the heat. The thermostats will need to be able to schedule the on/off times for the rooms (see below* for why). They obviously also need to detect the ROOM temperature! On top of this, only you can decide what else you need. Wi-Fi linked,controlled by an app, and/or Alexa etc. Do you need to be able to control your house temperature from your sun bed in the Algarve? How do you control the heating if you lose your wi-fi...etc Only you can decide on these options, and there are lots of them.....

    Next

    ZONE CONTROL BOX*
    This is just a time switch for the two zones. The new thermostats will have the time control, so it will be redundant.
    You have two choices:
    1. Just set the time controls on the old box to always on,
    or
    2. Get rid of the box and permanently connect the power. I would install a simple double pole switch (32amp minimum) so you have a simple means of isolating the heating.

    Hope this has been some help. Please let us know what you decide and on progress!

    Cheers

    Bazza
     
    Last edited: Feb 15, 2022
    SIRJOHN19 likes this.
  20. CeilingFan

    CeilingFan New Member

    @Bazza Thanks for the reply and apologies if I hijacked. I'm not after an external (outside) sensor, I'm after a remote sensor that I can put on the wall (or table, whatever) in the room so it can send back a hopefully more reliable temperature reading to the now not-in-the-best-place hard wired thermostat. There is no option to move it.
     

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