I have a similar boiler/thermostat to the one in the article, and my thermostat also tends to cut out once a year or so. I tracked that down to the battery ter

I have a similar boiler/thermostat to the one in the article, and my thermostat also tends to cut out once a year or so. I tracked that down to the battery terminals corroding quite badly, and once the oxide layer is removed the thermostat works fine again for the next year or so. It's still an impressive bit of reverse engineering though.