Electric baseboard support


#1

Hi everyone,

As electricity is pretty cheap here in the white north (Canada), we have a bunch of basic of 110V electric baseboard scattered around the house. Reading through the the forum it wasn’t clear to me if hestiapi would work out of the box with electric baseboards - does it support them?

Thanks.


#2

Are you referring to electric baseboard heaters ?


#3

Sorry, yes I meant electric baseboard heaters. Namely ones that can consume >1000W or more.


#4

Do they get controlled centrally or individually with their own switch and thermostat?


#5

Each thermostat only controls 1 or 2 baseboards on the same room and they have a sticker on them that says 240VAC (I mistakenly thought they were 110V).


#6

Assuming there is an intermediate relay that can handle the load once triggered by a mains signal, HestiaPi can connect to it and provide the control from the LCD/App/Web UI.
In an ideal world, if you are into electronics, you can hookup a Sonoff/ESP (per baseboard or set of baseboards) over WiFi via MQTT to HestiaPi and assign it to each room so that you can have a separate control page of which rooms should be activated each time the heating is activated. Even further, you can arrange this as Scenes/Scenarios like Work (all off), Movie (only living room) or Bedtime (only bedrooms).


#7

I’ll look into this. I actually have a bunch of Sonoff modules which I use to turn lights, fans, etc. (not the high power ones though - I’ll order some of the ones rated for 16A, although I’m somewhat scared to entrust the safety of the house to a 20 dollar module. Do you have any suggestions on adding any safety features to them? Or they should be pretty safe even connected to a >1000W load?


#8

Here are some possible points of failure I could think of:

  1. Power failure on the module
  2. Communication failure on the module or the home WiFi network
  3. Relay failure on the module

Let’s see a few possible solutions against these that can be implemented (same numbering for reference):
(Needless to say, someone with good knowledge on electrical loads and wiring needs to be consulted beforehand)

  1. Failure means that the module will be dead, so the relay will stay OFF. A notification can be sent to your phone if after X minutes heating hasn’t risen Y degrees. X and Y can be defined in the settings. An additional failsafe relay can be added in parallel to the first if underheating is critical
  2. Same as 1. but failure may occur once the relay is ON so it will stay ON. Another notification can be sent to your phone if after X minutes heating rose another Y degrees. X and Y can also be defined in the settings. An additional wired failsafe relay can be added in series to the first to cut power completely. Obviously a good healthy (potentially isolated) wireless network is something that needs to be taken into consideration.
  3. Although the relays used by Sonoff are industry standard, surely they can fail (if you are really unlucky) at the same rate as some consumer thermostats. To half the chance of failing stuck ON you can use a set of 2 relay modules, one for L and one for N lines that listen to the same signal. Similar to 2 an additional (wired or not) failsafe relay can be added in series to the first to cut power completely. Lastly if high loads increase the chance of a relay getting stuck, you can “outsource” this to an (expensive) solid state relay (SSR) that is paired to a standard module like Sonoff for the signal. SSR are exclusively used in HestiaPi for some time now as they have a much higher MTBF. To push things even further you can “design” your own module with an overengineered PSU, SSR and WiFi module and take control back :wink:

As a last resort you can add a “manual” bimetallic thermostat on the heater if all your measures fail.
I don’t think you can ever eliminate the ‘chance’ of any type of failure but you can simply plan ahead and work around these beforehand.


#9

Hi,

thanks a lot for the detailed suggestions.
All of those failure modes are quite tolerable for me if the end result is be replacing the module.
What scares me if they come accompanied of some melting/burning of the components that could cause a fire.

thanks again for all the details.


#10

Then you can focus on my last suggestion:


#11

I don’t trust myself enough to do the high power HW part. I can do the SW part and all the low power ESP8266 FW, etc. On the high power part I would probably do some stupid mistake and burn the house down :S
I did find pretty much what looks like equivalent of a Sonoff POW but for high power, and ‘looks’ pretty solidly engineered: https://esp-market.com.au/products/heavy-duty-wifi-switch, however I cannot find any detailed specs/certification on it (although it’s not with an SSR).
It would be great if you guys had some partner that would provide a high power switching board (or you made your own) - not sure how big the market would be though.
What attracted me to the HestiaPi was that you provide the boards and you support easy to interface protocols like MQTT that I can connect to my HA. I’m not a fan of systems that require online accounts to control stuff in your house. Like this thing “https://shop.getmysa.com/products/mysa-baseboard” looks fine HW wise, except they refuse to add MQTT to it, or open it up a bit so other people can do it.