There is also one tap in the house that is used to provide hot water directly from the gas boiler instead of the cylinder - Something to do with making sure the 'diverter valve' does not fail and has regular use.
The nest thermostat setup has worked flawlessly for just over a year and tonight when I wanted to heat up my sons loft room, the rads would not get hot.
I firstly checked the nest thermostat and it mentioned it had an issue connecting to the link. I tried to reconnect and it connected straight away (this happens from time to time due to the distance of the thermostat and link).
I then went to check the boiler and it was not heating up although powered on.
I checked the single tap that heats up using the boiler directly and this worked instantly.
Going back to the nest, I then attempted to heat the cylinder up, which again worked - boiler was in operation, same applies for the kitchen.
I then tried to set the thermostat to high temperature (23 degrees) and whilst the nest goes orange and says it is heating up, nothing happens at the boilers end.
At closer inspection and playing with the thermostat from getting the boiler to heat up and off, I can clearly hear click at the links end when it is calling for heat yet no impact on the boiler.
What could be the issue and how can I resolve it please?
I have 3 young children and the loft bedroom currently is at 15degrees and dropping!
Attaching a pic of the boiler in hope it explains the setup better
