Lol yeah I know the feeling it’s because of the recirculating back to tank when I’ve had it very hot,what I’ll do from now on is start it off on minimum recirculating it back it would have cooled down in the end but the exchangers would have been piping hot having it on full heat.
It’s not a problem on modern glass so much although you still have to be careful it’s the older glass you have to watch it on,if you clean roofs for free like me it breezes through em 😂