I have had two next thermostats fitted to my regular boiler with no issues. I have three zone valves (Upstairs, Downstairs & Hot Water). All were working with no issues. Then I had a failed heat exchanger on the boiler and the system was off for three days. Since the heat exchanger has been replaced, I have had issues with the nest controlling the heating and hot water. It works for a while then stops working. I have reset all the heat links and reset the nests and all are connected to the heat link with no issues. Each time I turn on either upstairs, downstairs or hot water I hear the click but the boiler is not firing yet they are showing as orange as if they are heating. The downstairs is directly wired in and the upstairs is wirelessly connected to the heat link. The work they did had nothing to do with the wiring so cant see why this is now an issue
