Ah ok, I assume to see the circuit board someone needs to actually open those module. Ok. So the question I have is: are those pcb modules ((in those dimplex heaters) only used in to control the night heat storage function? Because if the day heating works the pcb modules would not be "connected/responsible" for the day heating - would they? Unless some elements in the pcb module is responsible for the night and some other parts for the day heating? Sorry just trying to understand what the pcb are responsible for and on the web it only says that they control the temperature.if the circuit board itself has big brown burn marks on it, it will need replacing with a new one.