Mitsubishi MELCLOUD integration with Home Assistant

I’m sure that some will see this as far-fetched and it goes well 9 out of 10 times, but I’ve seen ESP32 development boards without any protection before their regulator. Or weird fuse+regulator combinations not tailored for the application. No over voltage protection, no thermal shutdown, GPIO that connect straight to the TX/RX, no EMC shielding. Best case in worst case scenario is that the ESP dies and all you notice is that the A/C is non-responsive.

But what happens if the regulator of the A/C gets overloaded(due to components failing on the ESP board) and fails? Will it pass through 12V+ to the board? Can the ESP regulator handle that and if not, will it overheat and start to smoke if it shorts? How reliable is that fuse anyways and is it fast enough? I’ve seen no-name fuses getting desoldered by themselves instead of breaking the circuit. I have no idea how well that CN105 supply is designed internally, so I don’t know if it would pass on voltage spikes to the ESP as well in some events. Especially when people use $3,- boards, that’s so super cheap that manufacturers have to jump through hoops to get to that price. And then of course there is the trivial things of accidentally connecting the wires to the wrong pins.

Yes I know many people use these boards from aliexpress as-is and it works well for many, but the A/C and ESP is powered 24/7 and especially when I’m on holiday I don’t want to have to worry if all keeps working fine and my house isn’t going to burn down, how small that chance may be.

I’m certainly not saying don’t do it. Have fun programming! soldering a cool kit and save some money in the process. It’s a great feeling. But, people should be aware of the risks.

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Hi, I don’t know if this belongs to here or to github. I’ll move my guestion if needed.
But I have an issue or functionality that I’d like to work differently.

Integration is working just fine with my LN25 air-to-air AC, but whenever I change the target temperature from AC’s own remote that change is not reflected to HA integration. Not unless I change the HVAC mode temporarily from HA - then it might read the new temperature, but not always.

MelCloud official mobile app can see the temperature regardless of the way I’ve set it. Either trough remote, melcloud app or homeassistant.

This would be super handy to see the temperature changes in both ways to homeassistant as I’ve set an automation for the electric radiators to automatically follow the AC target temperature via their own automation. Not directly the same temperature but depending of selected scene they will either be 1 or 10 Celsius below the AC’s target temperature (to save electricity, but to make sure that our cabin heats quickly if needed)

If HA could see the temperature changes in relatively real time - I could avoid installing a additional physical buttons for those users who wish to control the temperature without homeassistant app on phone. And electric radiators would follow the temperature change.

I have the Ecodan Air to water heatpump. Have anyone found a way to control the timer when to heat tap water via HA?

Currently I am using the built in timer function. It only allows hot water to be made between 19:00-09:00,i e during night. The reason I did this id because the immersion heater kicks in if outdoor temp is 22+. However, in sweden we have wild temperature changes. one week it can be 28 degrees outside and the next week only 15.

This is what I would like to do:
HA automation runs every morning at 09:00.
It checks what temperature is expected during noon.
If temp is above 20, enable the timer.
If temp is below 20, disable the timer.

Perhaps there is an API call that could be made? It’s basically this I want to change:

A possible work around could be to remove the timer entirely and then let the HA automation set the hot water temp to something low if outdoor temp is high and then increase it again.

of all the projects with esp32 and mitsubishi heatpumps, how many reports have you seen of broken units caused by the esp32? I only know one guy who manage to do it, but he wired esp and procon in parallel (not something you want to do).

Why I actually recommend the m5 atoms3 is that they do specify what they use.

and here is the long list of successes Please ONLY list your unit types that work, don't ask for support! Use Chat for that. · Issue #13 · SwiCago/HeatPump · GitHub

when connecting to cn105, you normally don’t need the 12v. 5v will power the esp32 fine. I only noticed that a procon would require the 12v. btw for all the concerns you mention, there’s no detailed explanation how climacontrol deals with it. I would not buy anything without clear specifications.

there’s no known way to do this. But with some local solution, you can enable server control mode. In that mode you can issue a “start heat water now” in eco mode (prevent unwanted dhw via prohibit, enable dhw when you need/want to).

You can always do a forced hot water, but that ignores the eco mode flag.
The timer mode in the ecodan is also weird. if you set it at a certain time, dhw always starts. It does not look at max temp drop.

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I opened a discussion section for this project and probably won’t post a lot here anymore. Don’t want to hijack things.

Huh, I had no idea that “Force hot water” ignores the eco setting but I guess it makes sense.

The lowest temp I can set is 40 degrees. Perhaps I could set it to 40 each morning and then increase it to 53 when its 20 degrees outside or something.

Regeding your code for esp. What is the difference of feed temp and boiler temp? Only 2 types are returned from melcloud integration?

yep. If you monitor the frequency you will notice the difference (80hz vs 60hz in my case).

Most ideal solution is to activate dhw prohibit flag. This can only be done via server control mode (you need a local solution for this). you can then able dhw when you want to.

with melcloud wifi adapter, I think you have 2 choices:

  1. set boiler target temp to lowest value, and max drop temp to highest value. This tries to prevents unwanted dhw. You probably want to prohibit dhw during the night as well.

  2. enable and disable vacation mode. the heatpump will always start dhw after on/
    off

  3. turn on/off the unit (stand by). the heatpump will always start dhw after on/off

boiler temp: temp sensor value that the heatpump uses to trigger dhw when it drops below your max temp drop value
feed temp: the current temp that the heatpump produces to warm up the boiler. In heating/cooling it will show the water temp that the heatpump produces for the selected mode/target temps.

in your screenshots from top to bottom:
feed temp
return temp
room temp setpoint (I guess)

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I see. Thanks. Yeah I have the room thermostat, that is the last one.

Not sure I get it though. Feed temp is the temperature leaving and entering my radiators for example? And boiler temp is the temp between the indoor and outdoor unit? :face_with_raised_eyebrow:

boiler temp is the temp in your dhw tank (“thermostat value of your hot water tank”).

feed temp is the temp that “leaves” the heatpump given it’s current operation mode
for example:
dhw mode: it can produce something like 50C to heat up the dhw tank
heating mode: it can produce 30C that it will send to your radiators or underfloor heating

It might be wise to watch/read some heatpump principle videos/documentation.

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Aha ok, thank you. :smiling_face: