Plugged it in for the first time since last autumn to wash the car and nothing happened at all – completely dead (no visible or audible signs of life at all). I tried swapping out the fuse and double checked that the mains socket was working but it was utterly dead.

Switch on the unit goosed? Anything else?

Do you bleed it every time you use it? If not, likely it’s dead. Otherwise check the fuse and or different power point?

Do you bleed it every time you use it?

No, never have. Why would that break it though?

Otherwise check the fuse and or different power point?

See my OP 😉 I tried swapping out the fuse and double checked that the mains socket was working

Is there a chance that any water left inside it could have frozen and broken something?

Air lock in the head causes the cylinder to overheat. It’s dead. You need to run them with the power off until water comes through without air. Then turn on.

Ah sorry saw you tried another plug

http://www.karcher-help.com/index.php?/Knowledgebase/Article/View/4/0/why-doesnt-my-pressure-washer-reach-full-pressure

I’m that sad. But in my defence mines still working happily after four years and about to get used later after MTB ride.

Is there a chance that any water left inside it could have frozen

It is kept in a garage and it doesn’t get below freezing (our boiler is in there)

When my Karcher packed up last year I took it apart to find the capacitor had “exploded” for want of a better description. Approx £10 from espares and it is good as new again.

Yeh, mine is just the same. Only used it half a dozen times,but out of warranty 🙁

TBF, mine had lasted about for or five years I think and got a hammering last year cleaning all my drive/footpath but I am very disappointed that I am going to have to fork out for a new one.