This has enabled the possibility to program a "powerlimit" on my heat pump. Since I have 15 heating zone's in my house, I always had the program of the heating pump running at max power when a zone with relative cold water opened. Now I monitor this and lower the flow temperature to prevent this. It also increases the flow temperature when possible to the requested max temperature. If I want I could even heat my house based on power input instead of water temperature input.
I have a similar to translate to and from MQTT, and have patched it into Home Assistant
As I don;t have Melcloud, I was looking at this pic..
From the MElcloud site
Just trying to work out which features are left to find
From what I can see, it is possible to Set Zone 1&2, Room Temp, Flow Temp, but not adjust the compensation temp... We have found that too..
You can adjust the DHW setpoint and turn on 'Boost' ... We can do that too
On Melcloud, it looks like you can setup 'Holiday MOde'
I was hoping we'd be able to set the heating and hot water between Off/Timer/On, like on the FTC5, but I can's see that
Have I missed anything major?
That one you mean?
Nice, I will try it this week ;)
Hi all, I saw your thread on tweakers.net and am very interested in getting this running @ my home as well (Mitsubishi Ecodan owner). Currently I'm running a WeMos D1 to force a 10 minute duty cycle on the thermostat input, so adding this to get readings from the heatpump in my OpenHab installation would be very nice :-)
@BartGijsbers any suggestions on where to get the level shifter? I have a lot of stuff lying around except for that. I would like to play around with your code to implement the homie standard (https://homieiot.github.io) so compatible controllers like OpenHab can automatically recognize it.
Welcome to the team Rob! I am using this level shifter: https://www.aliexpress.com/item/32772428392.html?spm=a2g0s.9042311.0.0.27424c4d3Cpscp. I think am level shifter will do to be honest. I am also controlling the thermostat input with a D1 mini already for years. I build my own thermostat/zone control. I don't know if you can get my code running on a D1 mini. The esp8266 has only on hardware serial port which is wired to the usb chip on a D1 mini.
As I understand it.. The Ecodan must have an 'Open Collector' output on the TX pin, ( https://en.wikipedia.org/wiki/Open_collector ) That is why you need a pull up, and don't see data if you don't have one. You can 'pull up' to any voltage you like ( within reason ), so if you pullup to 3v3, you get 3v3 logic levels, pull up to 5v0, get 5v0 logic levels. You can add a pull up resistor externally, or as the data rate is so low, and if your cable is short, the ESP8266 ( and others ) allows the option to enable an internal pullup. Using this, as the ESP8266 isn't 5v tolerant, you are sure you only get a 3v3 input to your D1 ( or similar ). For the Ecodan RX pin, it may be 3v3 logic on board, or 5v, but both see a 3v3 signal as logic 1, so there is no problem So my case I have both Rx and Tx directly connected, with "INPUT_PULLUP" set on the ESP8266 Rx pin, and it all seems to work OK
Good job guys. I am also very interested just lacking time. You can use the Rx and Tx (from usb) of the ESP8266. connect a diode from the Tx output" Edocan" to Rx input ESP. (pull only to gnd) I use this myself for ESP8266 to RS485 to MODBUS.
Normale there is a resistor between USB TX to ESP8266 RX.
Normale there is a resistor between USB TX to ESP8266 RX.
Hi guys. I stumbled uppon your project as someone mentioned my name on a forum. You guys are doing the same as me and some others started a year ago with the panasonic heatpump. Now a year later we are very succesfull and have a large user community for the project. I'm reading you are facing the same problems we had before. We now even have our own board which can be easily connected to the panasonic heatpump. See https://www.tindie.com/products/thehognl/heishamon-v31-communication-pcb/ And the thing is, this board is almost 1on1 compatible with your mitsubishi heatpump as it seems. It only uses the older esp8266 instead of the esp32 but that would be no problem. Panasonic is even using the same 5 pin JST connector of the mitshubishi ! So, to conclude, if I can help you in any way let me know. I would be pleased to send one of you guys a heishamon PCB with cable so you can test it out (you only need to switch some pins as the pin order is different).
Hi Igor, welcome as well!. That looks impressive what you have made. I make custom circuit boards, but don't know if I will make it for this project. The idea to include temperature sensors is great. I now have a separate esp for that.
@BartGijsbers I mean, you can use the heishamon pcb without a problem when you install the esp8266 code on it (with some minor changes I will provide, we use gpio5 to enable lever shifting mosfets after boot and use serial.swap so we do not need to use the normal tx/rx). If there is a mitsu user near Arnhem/Nijmegen (Netherlands) I will be happy to come over and test this.
Yes this is why we did this in the first place. However the replacing GPIO's after swapping need some special care also or else the esp8266 will not boot up. So GPIO5 is used to enable the mosfets for level shifting after boot. This is also described in the esp8266 hardware design guide page 11 and 12 (https://www.espressif.com/sites/default/files/documentation/esp8266_hardware_design_guidelines_en.pdf)
I am ok to send you a pcb and a cable if you PM me your adres. It however needs a USB-TTL cable to program (or OTA afterwards). Do you have that? Or else I need to program your software first on it so you can OTA update it later.
I am ok to send you a pcb and a cable if you PM me your adres. It however needs a USB-TTL cable to program (or OTA afterwards). Do you have that? Or else I need to program your software first on it so you can OTA update it later.
Ok great, let me know when you want to test. The problem we had with the pana is that they pulled the GPIO15 high (on their side RX while TTL communications state that the TX side (wemos gpio15) is the one who should pull it high and not the RX side). This caused the wemos not to boot while connected to the heatpump so we needed that mosfet enable solution after boot.
Great project guys, much appreciated. I'd like to help out where I can (I'm a professional software developer), but the hardware part is not really my cup of tea. Would anyone care to give some more pointers on that? And if there is any possibility to ruin the heatpump with this?
Welcome Tim. At this moment we have the gateway software running on a "standard" esp32 development board. The next step is to have it run on a standard esp8266 development board (wemos D1 mini). After that we can try if the software runs on the heishamon board. We don't know if we can ruin the heatpump. With setting commands we are very carefully and only write settings which we have reversed engineered. This reverse engineering is done by listening to communication between a melcould interface and the heatpump. Here you can see what we have found so far: https://github.com/m000c400/Mitsubishi-CN105-Protocol-Decode. In my code we have implemented that: https://github.com/BartGijsbers/CN105Gateway-production
Hi @BartGijsbers , I've built a board based on a ESP32 just like you to get started :-) I wanted to double check the pinout on the Ecodan, do you happen to have the color/pinout mapping? My cable has the following cables: red/brown/orange/yellow/green. I've read somewhere that pin1 is 12V?
Also, I'll fork your code on Github to make some changes. I'm using platform.io and it's quite picky regarding C-style forward declarations (whereas the arduino studio works around that in the background).