Wire fell out of terminal on underfloor heating - help.

[xanthophile]

I am a spark and while testing new cabling today a wire fell out of a terminal in an underfloor heating wiring centre/control box. Have looked at some wiring plans but can't sus where it came from. Please see diagram of PCB. Thanks for your help.

 

[picasso]

I "think" its a permanent live, the grey to the 2 port and supply to what ever switch LR (which is the supply to open 2 port ) normally needs a permanent live, but you need to trace it.

 

[xanthophile]

That picture of a switch between LS and LR is an image marked on the PCB.

 

[Jackrae]

Forensics required
Look at all terminals to see if you can identify where the wiring came from ie an obviously loose terminal screw
That's one of the reasons why all unused terminals should be screwed down during installation then it is evident that that terminal hasn't been used if a wire falls out.