Cannot communicate with Intergas Kompakt HR 22

[rcambrj]

I have an Intergas Kompakt HR 22 and normally it's connected to a Honeywell T87M OpenTherm thermostat.

I've put this basic OpenTherm sketch onto an ESP8266 (Wemos D1 mini) which has a DIYLESS Master OpenTherm Shield on it, connected it to the boiler instead of the Honeywell thermostat, and all I get is:

Error: Invalid boiler response 0

Pins are correctly configured:

const int inPin = 4; // D2
const int outPin = 5; // D1

I'm not entirely sure how to move forward with debugging, any help would be appreciated 😢

[craigsbits]

Possibly unable to assist but I am about to try the same configuration (waiting for new boiler). Just to check is the web http page giving sensible response - looks ok! Might be worth swapping ot1 & ot2 wires I know it should not matter but....

[craigsbits]

Oh flip I am a whole year out from everyone else!!!

[wjaszczuk]

@craigsbits it seems I'm facing the same problem here. I'm trying to use a gateway between my boiler (Immergas Vitrix II Zeus ErP) and the official thermostat - CAR2.
I'm using WEMOS D1 mini ESP8266 and I always get an Invalid response there.
The voltage between OT wires is something about 6V. When I use CAR2 there is 24-25V.

I tried to swap OT wires - it didn't help.