Home DIY

I am totally at sea with my Nest failure - here's what has happened:

• The cabling, which has worked for two years, is the same
  
• However, the setting on the boiler of "on" which used to be the one for the Nest, now gives the timing dial on the boiler command, and ignores the Nest
  
• If you move the selector to the timing dial, the timing dial has command
  
• Off is off
  
  

I have no idea.