First let me apologise for resurrecting such an old thread. However, I have this exact boiler (ZWBR 11-35 R 35 HE plus with TR2) and followed the advice given here to get it working with a Nest 3rd generation. I wired it as per mthorniley diagram also unplugged the TR2 and it works, the nest calls for heat and fires the burner correctly. However, when I look under info in the text display panel the burner switches on and off but the pump is always running. You mentioned a workaround? Is it possible to have a Nest working with a ZWBR 11-35 R 35 HE plus?