vaillant ecotec pro28 problem

I woke up this morning to find the heating hadn't come on. I then noticed the downstairs mains plugs circuit had flipped. I flipped it back on and went to the boiler which was saying f22 (dry fire) and 0.4 bar.

I cannot see any leeks anywhere so cannot see how it could be 0.4 bar.
Also I don't know if the bolier caused the electric short or if the short caused the boiler fault. The boiler is the only thing that would be active that time of the morning.

I added some water to the system and it now shows 1.2 and is now working. but I am concerned is the boiler showing the right pressure now? and what caused the issue????

Any ideas?
I am calling out my installer but dont think it will be anytime soon.

I plan to vent the rads then run the self purge.

A short would not cause the boiler to fault to F22.

However a leak somehere on the system could have run into some electrics and tripped them out.

Thats what i'm worried about. There's no leaks from the rads anywhere. I've no way of checking elsewhere though. I've refilled and purged so will have to keep an eye on the bar.

Pressurise the boiler then isolate at ch valves. Leave as long as possible, if pressure doesn't drop leak will be on system somewhere.