this is only a grumble because I have been able to fix it....
Last night I thought I had a sudden power cut, but then I found the RCD in the fuse board had tripped. So I reset it, listened to all the bleeps as various devices powered back on and then click it was off again. So now it becomes a question of turning things off and turning on the RCD to find the culprit device, previously this was a heating valve but I had replaced the actuator in November and thought the issue solved, however the delay was rather indicative of the heating system so I turned off the boiler and turned on the power. It stayed on.
House was working and I could make diner but no heating or hot water. The next check was to try the boiler but with only the hot water, click, darkness. OK more investigation needed. Open the airing cupboard where the cylinder and valves are and why is the carpet wet.
Long story short the spindle seal on the valve has failed and the water has got to the solenoid actuator and the limit switch hence the power outages. Further proven when I took the actuator off and disconnected the wiring at which point the hot water worked without issue. Fortunately replacement valves are readily available and so, after ordering online, at 8am this morning I could collect a new one from a local merchant.
Then came the task of draining the system, undoing the valve, splitting two other joints to allow the pipework to spread far enough to get the valve out, getting the old olives and nuts off, install the new valve, refill the system, start the pump an bleed the radiators. None of which I had planned on for today as I was planning to be working in the garden in readiness for plants to be delivered next week end.