That works, but limits you to only two commands, instead of the more fine grained control the full command set offers.
Hi,
Could you expand on the connection of the diode on the Shelly1 and how you control that on HA?
I also use a Shelly 1, without any diode. When the Shelly relay is closed the heater works in ‘Eco’ mode, when the relay is open it is in ‘comfort’ mode.
That’s fine for me.
@Shaad so your shelly works in dry contact (I’m not sure of the expression, I’m French) ? I read that it was not recommended for radiators with a pilot wire, for a question of radiator components lifetime.
Oh really ? I will have to check then ! Thanks. 
It works as a dry contact indeed.
Aren’t we all french on this topic ? I thought ‘fil pilote’ was another french wonderfull idea that never got out of the borders… but I might be wrong.
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I think it’s very French.
Personally I would have done without the diode, but as I don’t know exactly how much its absence really damages the radiators, I prefer to use it. Especially for the price.
Besides the modes “comfort, comfort -2, etc…” do not really interest me. I just wish I could tell it to turn on or off via the “pilot wire”. The rest, I let HA control it.
I’ve read a few articles and could find anything about damaging the heater electronic without any diode.
Diode is commonly recommanded because it allow to use different order such as ‘off/on’ for instance.
For my personnal use, Eco and Comfort mode are perfect.
You’re mixing up two things here. You’re thinking of a relay cutting power to the radiator as a whole. That is indeed not a good idea and may damage it long term.
@Shaad is not doing this. He is just using the Shelly to send a command to the heater through the fil pilote. Keep in mind that there are 6 commands in total. Two of them require a microcontroller to generate, as they use precise signal timing. The other 4 can be generated using relays and diodes. Two basic commands can be generated without a diode.
Without diode, only a relay needed:
0V : Mode confort
230V: Mode eco
With a diode:
Negative half wave: Mode hors gel
Positive half wave: Turns off the heater
Of course all this is still mains voltage and hacked together flying circuits of relays and diodes operating at 230V are not a good idea. If your house burns down because of it, get ready to fight your insurance in court. See Taras post above (although that guy did something really stupid that was unrelated to the diode, but still).
Ok, that’s clearer
I thought that without a diode it was impossible to just send a simple command to the pilot wire. Thank you for this clarification.
So, is it possible to know the connection to make on the Shelly 1 to succeed in piloting in Eco/comfort?
Just plug the Fil Pilote on the Shelly 1 output !
When the Shelly 1PM switch in ON, your heater will be is ECO mode.
When the Shelly 1PM switch in OFF, your heater will be is CONFORT mode.
I would have prefered it in a reverse way to have to switch on the Shelly to activate Confort mode, but I’m ok with the current behaviour, it’s easy, works great, and has been 100% reliable so far for 2 or 3 months
If you want to use all 6 orders of Fil Pilote, Qubino has a nice Fil Pilote ZWave module.
Just for the record, I ended up using a Heatzy Pilotes (https://heatzy.com/pilote).
They are worth 50€ on Amazon and you should buy one for each heater but it was exactly what I was looking for. Very easy to install on any heater using a screwdriver and a Wago connector (or a “domino” block).
Then, you can use Devotics’s integration (https://github.com/Devotics/heatzy-home-hassistant) to have it as a climate device in Home Assistant.
I also designed a specific frontend card for Lovelace that you can find here: https://github.com/DanChaltiel/heatzy-pilote-card.
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But it’s cloud based non ?
Or there is local API ?
No, unfortunately it uses a cloud API.
Not sure how illegal it would be to hack the ESP8266 inside their product to connect directly (which would be awesome) but I don’t have these skills anyway.
You don’t use Zwave ?
I validate the heatzy that I already use to control floor heating / radiant panels (on the ceiling). When I bought the house there was a fairly old Delta Core energy manager with 3 zones. I kept only zone 1 (the two others, for radiators, were poorly distributed) by putting a heatzy in the place of the manager. It works just fine.
But for the radiators, if there are a lot of them, I find that the Shelly are more practical because 5 times cheaper and you can hide them in the wall boxes…
@Shaad I found on the forum a code to reverse the shelly command (not yet tried because I haven’t installed them yet) :
switch:
- platform: template
switches:
switch_state_revert:
value_template: "{{ is_state('switch.your_switch', 'off') }}"
turn_on:
service: switch.turn_off
data:
entity_id: switch.your_switch
turn_off:
service: switch.turn_on
data:
entity_id: switch.your_switch
Ahah, thanks. 
I’ve made a switch called ‘Mode ECO’, so I don’t need to swap status.
When I said I would prefer that it works in the reverse way, I meant that I would have prefered the heater to be in ‘Mode ECO’ when fil Pilote was not receiving any input, and switch to 'Mode CONFOR’T when it receive 230V because Shelly modules tend to be hot when they are ON.
Ah damn, not reassuring this story of heat. Were you able to take temperature readings?
Yes, all Shelly modules report their internal temperature, as well as an overheating alert and an overconsumption alert. They are really nice but sometimes get a little bit hot, always under the overheating alert threshold but still hot.
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They’re known to get a little hot. At least it’s not as bad as the Sonoff’s, who are infamous due to their tendency to catch fire. Did you flash Tasmota onto the Shelly ? There’s a bug in certain versions of Tasmota that created essentially a short circuit in the Shelly MCU due to an incorrect pin assignment, making it heat up a lot more (and probably damaging it long term). See here. Make sure to update to the latest version. Or just use the original firmware over local MQTT.
By the way, regardless of what method you use to send the fil pilote orders, since the protocol is unidirectional and inherently multicast, you can use a single control module for multiple heaters. Just connect the fils pilotes of pretty much as many heaters as you want together on a single module, as long as they are on the same circuit breaker. I use a Qubino per zone, not per heater, with up to 3 heaters together on the same module.
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Thanks, I’m using the original Shelly firmware and MQTT.