Your installer must love you if he's fitted a Keston:D
You need an RGI to look at it, fan/ APS related fault probably
Will they both be piped Jeff?:D
Speedfit on show is a no no, sign of a DIYer.
You need to convert it to copper to look nice
If you must use 10mm copper to the TRV, then solder a...
Never failed to repair one yet with PTFE
You will need to safely test if their is power going into the board.
Check the fuse on the board again, after that, testing plugs on the "outlet"...
Sounds as though the PCB may have died, assuming there is power to it.
Did it get wet when you changed the DV?
Hot water pre heat is switched on.
Press the eco button for a few seconds until it shows green.
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