In my house I have 3 circuits of floor heating elements, each is connected to single phase (230V) 16A fuse and on one of them I have Heatit Z-TRM3 connected via z-wave to my home assistant. Others are manually controlled dumb thermostats.

That thing works, but at least the particular one I got causes a lot of interference to the z-wave network, so I’m a bit hesistant to add any more of those.

Features I must have:

  • Option for a floor temperature sensor. Each thermostat has separate pipe going to the floor and the floor sensor is easy enough to replace, but it is a must have option
  • Air temperature sensor. 2/3 of the heating elements are in a concrete slab and that means that measured temperature of the slab very slowly affects the air temperature, so I need both. ESP32 or equivalent as a separate sensor might be a decent workaround, but I’d rather have both on a single unit.
  • Obviously the 230V 16A capability as that’s what they’re wired on and even if I don’t have 3kW elements on the floor it’s what’s needed to meet the code
  • Manual controls on the device itself. Should my raspberry pi running home assistant kick the bucket or some other major issue with the automations happens, I still need an option to control the device. And that’s a strict requirement, no bluetooth apps on the phone or anything, I must have manual buttons or some other way to control the thing without home assistant or any other smart device.
  • And addition to previous one: No cloud requirement. Allowing the device to the internet for a setup is fine, but in the long run it must be happy in a isolated network without internet connectivity

For the communication I don’t really care. I currently have only wifi/z-wave as an option, but if there’s something on zigbee which ticks all the boxes I can invest in a usb-dongle or a hub.

Price is obviously a concern, but it’s hard to set any strict boundaries. I won’t throw a 1000€ for a thermostat, but anything even remotely reasonable goes.

What are your suggestions for a situation like this?

  • doogstar
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    14 hours ago

    I have a similar setup with 3 different heating elements, each with it’s own different brand controller (who knows what the previous owner was thinking!).

    I swapped one out a few years ago for a Heltun which seemed to meet my requirements and is designed for exactly that. It is the older discontinued model running on 500 series z-wave, their newer ones run on 700 series.

    I had initially planned to replace all 3 with the same model assuming it was good - I haven’t (as yet) - it was a pretty new product and it was a bit buggy which made me hesitant. I have wood flooring on top of the concrete slab/ electric blanket in two areas and it’s advised to not heat the wood up too high as it causes shrinkage, unlike under ceramic tile, and sometimes it would not respect the max floor temperature setting. I went back and forth with their support about it and they were very helpful, giving me beta firmware to flash etc and I worked around it.

    For the last couple of years it’s been mostly stable and behaving. For whatever reason, it no longer lets me directly set the target temperature in Home Assistant which it previously did - I may need to dig into that as it would be handy sometimes, but I think it meets all of your other requirements, like on device manual control, no cloud, air temp sensor and floor sensor connection etc.

    There aren’t that many products out there that fit the bill, I was particularly struggling with ones that would let me set the max floor temp sensor low enough when I was comparing the spec sheets a few years back.

    • IsoKiero@sopuli.xyzOP
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      1 day ago

      at least the particular one I got causes a lot of interference to the z-wave network, so I’m a bit hesistant to add any more of those.

    • IsoKiero@sopuli.xyzOP
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      2 days ago

      Interesting product, but based on a quick search online it seems like they don’t have reseller on the EU. PWM or any other kind of modulation isn’t really necessary on my use case, as the building itself dictates that the floor sensor should just keep the full power on until the set temperature is reached. It doesn’t hurt either, but as there’s no availability around EU then I just can’t get my hands on one.

      And even if I did, it most likely isn’t sold here for a reason, and I’d be pretty hesitant to install that on my house for insurance and other liability reasons.

  • jubilationtcornpone@sh.itjust.works
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    2 days ago

    I’d rather have both on a single unit. - Obviously the 230V 16A capability as that’s what they’re wired on and even if I don’t have 3kW elements on the floor it’s what’s needed to meet the code

    I have a feeling that finding a smart thermostat with this kind of load capacity, on three separate circuits no less, is going to be a tall order. Are you savvy enough that you could wire up a system that uses a regular thermostat to control your floor heating via relays or contactors?

    • IsoKiero@sopuli.xyzOP
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      2 days ago

      I think here’s some misunderstanding going on. I want 3 separate thermostats which each control their own circuit, as they are now, not a single thermostat which could in itself control each of the 3 phases. Thermostats are on different rooms (and even floors), so I need different measuring points as well.

      But, as the floor heating has very slow impact on actual room temperature, I want (and need) the option that the resistive wire on the floor doesn’t get too hot, but it still has an input from the actual air temperature on the room, so the thermostat can adjust that as needed.

      The Z-TRM3 ticks all the boxes on paper, but it’s causing problems on the Z-wave network itself, so I’m not too interested to add any more of those to the system. Also with that there’s option to just turn it off via z-wave and I haven’t found a simple way to re-enable the heating from the thermostat itself, so while it gets the job done it’s not optimal solution.

  • just_another_person@lemmy.world
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    2 days ago

    Maybe I’m reading your post wrong, but it sounds like you’d just buy a few cheap temp sensors, then use HA automations to read those and take action with the thermostat control to get your desired affect. So everything would work manually, but HA being alive would give you the added benefits of automations. Moe’s makes a bunch of thermostats, and their stuff is warranted and solid (I haven’t had issues at least). Have a look there.

    • IsoKiero@sopuli.xyzOP
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      2 days ago

      Interesting product line, but I didn’t find thermostat from them which would work as an replacement on the existing dumb thermostat. I could of course switch the thermostat to an contactor and control that via whatever, but I still need the thermostat functionality without any additional connectivity than the device itself, so at least based on a quick glance, I didn’t find a product which would fit my needs.

    • IsoKiero@sopuli.xyzOP
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      15 hours ago

      I have just the normal 3x25A on main breaker box. So only about 17kW available for my house and garage.