currently all my radiators are equipped with Danfoss LC-13 thermostats, like this one:
Unfortunately with one of my radiators, the thermostat is placed in a room corner, below a window sill and with a curtain covering it - which makes it nearly impossible to read the correct room temperature as heat easily accumulates at this spot.
In the “old days”, that radiator had a thermostat with a remote sensor that attached to it, like this one:
I am now looking for a solution/product that allows me to read the room temperature at a different spot than the location of the thermostat - and to control the thermostat or valve accordingly.
I have a Multi-sensor installed in that room that allows me to get a more realistic reading of the room temperature, but it’s not feasible to use that with the LC-13 thermostat since the LC-13 is only controlled by setting a target temperature and then it tries to adjust the valve opening based on it’s own temperature reading.
So basically I need some “dumb” Z-Wave valve and a remote unit for the temperature reading and valve control.
Ideally this would be some kind of integrated solution where I only “talk” to the controller and tell it to adjust the room temperature to e.g. 21°C (I’m not eager to implement my own control-loop via a HA automation based on temperature readings and valve positions).
I would also not need some kind of fancy “physical user interface” like, e.g. the Nest thermostat, though a means to manually set the temperature would be appreciated.
Does anyone have a product recommendation for that use case?
It’s pretty hard to google for products since “thermostat” apparently is used for both device types, the ones I use and that attach directly to the radiator (valve) and those Nest-type thermostats that are only control units.
Hm, to me this looks like the same type of device I already have.
You set the temperature at the thermostat and it uses it’s own temperature reading to control the valve.
I don’t see any possibility to attach an external sensor.
But, if it only worked like that, what will be the use of the Z-wave part?
I assume, that somehow you can control it from outside too, just need to figure out, how.
And other ways, You could use you second temperature reader to figure out the temperature difference and just set the valve to the desired temperature+the difference.
Like:
On the valve it shows 18. But inside the room it shows 21.
You want 23. Set the valve to 20.
It uses Z-Wave to communicate the status to a “controller” (be it HA or the unit that Technisat offers) and it can be controlled remotely, i.e. you can set the desired temperature from the controller (and e.g. use the controller to set up a heating schedule).
That’s exactly what my existing thermostat does as well - there’s also a control unit from Danfoss for people that don’t want to set up an automation system like HA.
Of course, I also had the idea to simply adapt my target temperature setting to the difference to the actual room temperature. Unfortunately that difference is not a constant.
For example, I want to have about 21°C room temperature and, with the higher temperature at the thermostat location factored in, I set the thermostat to 25°C target temperature.
Now I’m moving my curtain a little further away from the thermostat (that happens regularly) which improves the air flow at the thermostat.
Suddenly those 25°C target temperature are too much and the room heats up beyond what was intended.
So now the actual room temperature can be controlled by the curtain position
Not ideal.
I’ve had mine for a few years now - it doesn’t have that direct valve control option.
The function does sound like it’s what I wanted - but it would also require me to program my own control loop, which I wanted to avoid.
I’ve also found a review of the StellaZ that doesn’t recommend the device (besides, personally I don’t like the optics of that thing).
I was hoping to find a recommendation from someone with the same use case, but apparently not many users seem to have a requirement for a remote sensor in the way that I do.
I’ll keep on looking…
It looks like the Eurotronic Spirit Z-Wave thermostat (which looks suspiciously like the Technisat mentioned in the first reply) is able to work with an externally provided room temperature.
Unfortunately, no further details are given in the manual.
I thought so
I think I’ll give the Eurotronic a try. I wanted to ask in the ZWave subforum if someone had managed to get it working with an external temperature sensor, and there it was, right at the top:
Still need to go through the details, but it sound promising.
Thanks, I’ll keep that in mind as a potential alternative!
For now, I have ordered the Eurotronic Spirit and I’ll give it a go!
EDIT: The Fibaro actually looks kind of nice and apparently it’s available as a set with an included external sensor: amazon.de
It’s not cheap, though…
To wrap this up: I got the Eurotronic Spirit Z today and installed it.
Originally I wanted to try and associate it with the temperature sensor of my Fibaro FGMS motion sensor.
Unfortunately I noticed that the association groups of the Fibaro do not include the temperature readings - there’s one for motion detection and one for tampering.
Also, the primary group (which gets the temperature readings) is limited to the zwave controller.
So I’m now using the node-red Workaround posted in the thread I mentioned earlier.
This basically waits for a “temperature changed” event from the Fibaro sensor and then injects the value via MQTT into Zwave-JS using the API.
So far this seems to work pretty cool.
I have a similar problem. As I move around the house I like the LC13 in the current room to act a bit like a hall thermostat in a conventional system. I achieve this by setting that TRV to 28 (max) and all other TRVs to the desired temp for the house. Using 28C is a kludge to force the active room to behave as if the TRV is full open. Having an “open valve fully” z-wave command on the LC-13 would be much better but it can’t do that. I contacted Danfoss to see if a manufacturer specific command would be helpful but they were very cagey about their “trade secrets” ffs.
Then I use the temperature reported by the LC13 in the active room to turn the boiler off and on, much like a conventional app based TRV would. In essence, all other rooms are slaved to the active room, some may not reach the target temperature by a few degrees, but that is fine, saves fuel. I experiment using the average from several rooms but ran into problems with the (very well done) PIV algorithms closing the valves too early in the slaved rooms. So, after several years experimentation, the single room control and multiple slaves work best. If anybody has better ideas, I’m all ears.
The HA programming just uses t<21 for “boiler on” on and t>21 for boiler off where t is the temp reported by the LC-13 in the active room (with that TRV set to 28). Originally I had 20 and 21 to provide a little hystereses to prevent hunting but in practice both at the desired temp (21) seems to work fine. I have a table lamp slaved to the boiler while debugging.
Getting back to the original question regarding remote control. One of the rooms has a problem with curtains over the TRV. Problem was solved using an independent temp probe (Sonos Zigbee) instead of the LC-13 to provide the room temperature.
