Wiring
This is somewhere to collect comments and advice on wiring, leads, plugs/sockets, etc.
The connection to the Faikin module is S21, which will usually have 4 or 5 wires, wired 1:1 from S21 to Faikin.
| Pin | Meaning |
|---|---|
| 1 | 5V - not always connected |
| 2 | Tx from aircon - 5V logic |
| 3 | Rx to aircon - 5V logic but most models accept 3.3V |
| 4 | 12V, or 14V, or some such - used to power Faikin |
| 5 | GND |
If you have the existing Daikin wifi unit on a cable with 5 pin S21 plug, it is simply a matter of changing it to the Faikin module. However, in other cases you may need to obtain a cable and connect to your air-con unit. The S21 cable is one to one wired, i.e. pin 1 to pin 1. Note that Pin 5 is ⏚.
The S21 plug neede is JST, EH Female Connector Housing, 2.5mm Pitch, 5 Way, 1 Row, which needs pins and crimps as well.
WARNING Messing about in your air-con unit can be dangerous with live power, and could damage the unit. Take all precautions necessary and you mess with your air-con unit at your own risk! Note, X403 is a non isolated version of S21 so if you wire to that your Faikin will be live, so needs to be inside the case somewhere, and don't wire anything while the power is on... See X403.
There have been various discussions on this - Daikin appear to have a standard connector that is S21. They seem to have this in models that even have build in WiFi modules (see image). You need a JST-EH 5 way connector for S21. However the module can also be wired to units that have an X50A connector, with slightly different cabling. The discussions have various comments on this, but please do ask.
Another approach is "jumper wires" using header pins or sockets, e.g
It is also possible to connect to the S403 connector. The proper way to do this is with a Daikin S21 adapter board, as the S403 is not isolated, and use directly could be dangerous. This link has some more details of the S403 connector, as well as issue 134.
For X50A you need power from X35A as well.
