Home Automation Domotica Forum Europe, Bwired Forum

Hello OpenTherm Gateway (OTGW) Community,

I'm new here and recently purchased a pre-built OTGW (from https://www.nodo-shop.nl/nl/ons-assorti ... ilder.html) to start my home automation journey. My ultimate goal is to implement room-by-room temperature control using smart radiator valves, but I'm starting with the basic OTGW installation.

I've already connected the OTGW to Home Assistant, but now need help with the OpenTherm wiring.

Looking at the OTGW's 4-pin terminal block, I need help confirming the correct wiring connections:
- Which two pins connect to my existing thermostat?
- Which two pins connect to the boiler?

I understand polarity isn't critical for OpenTherm connections, but I want to ensure I connect everything correctly to avoid any damage to the device.

I've included photos of:
1. The OTGW board in its clear acrylic case showing the 4-pin terminal block
2. The inside of my current thermostat showing the existing wiring (blue/orange twisted pair)

Thanks in advance for any guidance on the correct terminal connections!

I expect the clear acrylic case to be clearer than your pictures show. Did you perhaps forget to remove the protective film from the parts? With a fully clear case you can see writing next to the 4-pin terminal block. The two terminals near the "Boiler" marking is where you connect the cable to the boiler. The to terminals closest to the "Therm" marking connect to the thermostat.

Thanks for your quick response ! I checked whether I could find protective film, but no luck. After (re)opening the case it was immediately clear where to connect the twisted pairs. Like you said, "Therm" and "Boiler" are printed onto the PCB.

Have a nice day!
Frits

I pointed out your pictures to someone from the nodo-shop. He confirmed that it still shows the protective film on there.

I found it easiest to pick at a corner using a fingernail to make a start at peeling off the protective film. The case will look much better without it.