Observations 1
a. If one studies Drawing 1 attached, one can observe that through the 4 pole disconnector (top left) and then the 3 white wires to above the 5 circuit breakers all the 3 white wires top left are joined together by the black busbar. This means these three white wires top left cannot be L1, L2 and N because a short circuit would have occurred rupturing a fuse or tripping a circuit breaker external to this enclosure. If a short circuit has not happened then they more likely to be of the same potential ie: a line or a neutral. The N, L1, L2 and L3 markings on the disconnector are to inform how it should be connected to such a supply if presented to it.
b. Studying further, one can readily see that each of the 2 wire digital power meters are connected across a 20A circuit breaker - this is incorrect. When the circuit breaker is closed the input to the power meter is short circuited and will not read any power consumption. In addition, the power meter requires an L and N at its input where only an L or N (yet to be confirmed) has actually been connected. I note the meters are reading zero.
c. The output side of the power meter connects to the input of a contactor by the blue and white wires and then from the output of each contactor to the floor heating elements ( I assume at this stage). Because only an L or an N (yet to be confirmed) is provided at the input to each contactor then no supply voltage will ever be connected across the elements - therefore they will not heat up. I suspect then that the underfloor heating system does not work at all at the moment.
d. The timer, albeit now redundant, still has two wires to it presumably intended as its supply - blue and white. Since these are derived wrongly from the two circuit breakers on the far right whose inputs are connected together by the black busbar there will be no voltage supply applied to the timer - it will not function.
e. From d), since the wifi switch has been tapped off the input to the timer it too has not voltage supply and will not function.
f. it would be impossible to measure with respect to earth the three voltages 230, 209 and 23V at the input terminals to the disconnector while it was closed because as mentioned when the disconnector is closed all the two sets of 3 white wires are at the same potential because of the black busbar.
It looks to me then that the wiring for the UFH was wrong from the very start or changes have been made which have resulted in a completely incorrect arrangement. Do you know the history of the UFH - did it ever work?
