Boiler not connected

[Juliennnn]

I would like to ask you a few questions about the OTGW.
After inverting the thermostat and the boiler connections on OTGW just to test, I cannot see the boiler anymore. Is it possible that I broke something on OTGW ? My boiler and thermostat still work together without OTGW.

I've installed the diagnose firmware on PIC, and here is the voltage levels result (test number 5 with boiler connected) :
Power supply: 3.276
Reference: 1.446
Thermostat: 2.936
Boiler: 0.000

Is it normal ? If not, do you think my nodo shop otgw is broken ?

In complement, I got these results :
Enter test number: 4
OK1A high-to-low: 11.25us
OK1A low-to-high: 22.75us
OK1B high-to-low: 8.50us
OK1B low-to-high: 4.25us

Opentherm gateway diagnostics - Version 2.1

1. LED test
2. Bit timing thermostat
3. Bit timing boiler
4. Delay symmetry
5. Voltage levels
6. Idle times

Enter test number: 5
Power supply: 3.276
Reference: 1.446
Thermostat: 2.124
Boiler: 2.773
Reference voltage setting (0..9) [5]: 5

Opentherm gateway diagnostics - Version 2.1

1. LED test
2. Bit timing thermostat
3. Bit timing boiler
4. Delay symmetry
5. Voltage levels
6. Idle times

Enter test number: 5
Power supply: 3.276
Reference: 1.446
Thermostat: 0.783, 2.127
Boiler: 2.757
Reference voltage setting (0..9) [5]: 0

Then :
Opentherm gateway diagnostics - Version 2.1

1. LED test
2. Bit timing thermostat
3. Bit timing boiler
4. Delay symmetry
5. Voltage levels
6. Idle times

Enter test number: 5
Power supply: 3.281
Reference: 1.448
Thermostat: 0.724
Boiler: 0.000
Reference voltage setting (0..9) [5]: 5

[hvxl]

The boiler interface of the OTGW is completely electrically separated from the rest of the device. It relies on getting power from the boiler. A thermostat also provides no power to its inputs. So connecting the boiler interface of the OTGW to a thermostat is the similar to connecting two powerless things together. Without power, nothing can be damaged. Also your other tests indicate that the boiler interface is still working.

You also didn't damage your thermostat or boiler, because they are still working together. So I suspect you just had a bad contact somewhere when you connected the boiler with the OTGW.