The Daikin Altherma version of the SGR dongle sports a power and data interface to Altherma 3 heat pumps, allowing it to be powered by the heat pump itself and report many measurements such as temperatures and flows.

What you will need:

• The Altherma SGR dongle
• A PTH cable
• (Recommended:) several meter of cable containing at least 2 twisted wire pairs
• (Recommended:) some wire screw terminals

Step 1: open up the heat pump

Follow instructions here.

Step 2: connect the SGR contacts

We recommend to run twisted pair cabling from the heat pump SGR contacts to the outside of the heat pump, so the SGR dongle can be placed outside of the metal heat pump chassis. This greatly improves wifi reception by the dongle.

Step 3: connect the power and data cable

Locate the X10A connector on the mainboard. This is a 5-pin shrouded connector placed semi-central on the heat pump circuit board. The X10A connector has the following pin-out:

X10A	ESP32
1-5V	5V
2-TX	RX_PIN (goes to TX on the dongle)
3-RX	TX_PIN (goes to RX on the dongle)
4-NC	Not connected
5-GND	GND

Depending on the version number of your Altherma 3, the X10A might be upside down. Locate pin #1 by looking for the encircled 1 printed on the circuit board.

Plug in the PTH cable, respecting the polarity of the connector. Be careful not to bend any pins!

We recommend to run twisted pair cabling from the X10 connector to the outside of the heat pump, so the SGR dongle can be placed outside of the metal heat pump chassis. This greatly improves wifi reception by the dongle. Use screw terminals to securely connect the PTH cable to this twisted pair cabling.