Thanks for your response mate, I am a bit new to this entire boiler setup. What do you mean isolate control box? I believed following the wiring on mthorniley diagram will help sort this problem and make Nest compatible but the side effects such as pump running?
Hi, Not sure if anyone is able to answer this...I am planning to install a Nest 3rd Gen thermostat but before i proceed i would like to make sure this indeed works with Greenstar R 35 HE Plus combi boiler. Simon, I see you are the last one who followed this post - did you manage to fix the issue...