Why have my Tado wired thermostats lost power (Com is dead)?


My Tado stopped working last night after a year without issue.

None of the wired thermostats are sending a signal to the receiver (they no longer "click" when you call for heat). Hot water continues to work. This lead me to test the cables for power and they were all dead.

Now in a very cold house, I switched the zone controller for one of the wireless stats to be linked to the main receiver rather than its actual zone controller (which is one of the wired thermostats). This managed to get the heating to turn on (proving that the issue is not the bridge) but more weirdly, it also led to the com in all of the wired stats to become live and now the rest of the thermostats seem to work.

I am unclear whether the Tado receiver controls power going to wired thermostats and why having the wireless stat "on" would cause power to run.

Do I have a fault with the Tado receiver or in the wiring of the system (which does rely on a series of complex relays). My intuition is that the problem has to be Tado?


  • policywonk

    Have you checked the battery in the wired thermostats? They may need replacing. If the batteries are dead, the relay wont work.

  • Seance
    Yes - all of the batteries are good (and the units work fine). The problem is that there is a dependency on the wireless stat being “on” for the power to run to the wired stats.