I still haven't ha a chance to check the voltages (my multimeter seems to have died and I need to purchase a new one).
However, solving a different issue around the house has resolved why the issue occurred... Rats got into the void under the house during the cold weather through a broken ventilation brick in a neighbour's wall.
While trying to close up any small floorboard holes to rat proof the house yesterday I discovered that the rats had completely eaten through the wire that connected the control box to the keypad...
So - I guess I should now assume that the units are all working OK and that the broken cable was what caused the fuse to blow - so I'll have to fit a new cable instead. I'm hoping I can get the wall unit off the wall, as the room was previously re-plastered with it in-situ, so it may be tricky - I haven't looked into how it is fixed - if not I could presumably always join a good portion of the wire leading from he keypad to the control unit at another location along the route.
However, solving a different issue around the house has resolved why the issue occurred... Rats got into the void under the house during the cold weather through a broken ventilation brick in a neighbour's wall.
While trying to close up any small floorboard holes to rat proof the house yesterday I discovered that the rats had completely eaten through the wire that connected the control box to the keypad...
So - I guess I should now assume that the units are all working OK and that the broken cable was what caused the fuse to blow - so I'll have to fit a new cable instead. I'm hoping I can get the wall unit off the wall, as the room was previously re-plastered with it in-situ, so it may be tricky - I haven't looked into how it is fixed - if not I could presumably always join a good portion of the wire leading from he keypad to the control unit at another location along the route.
