Boilerists to the forum...
Grant combi oil boiler - It triggered its overheat lockout after a voltage drop caused the circulation pump to stop.
I could hear water boiling in the heating loop / heat exchanger, and the whole lot was too hot to touch. I let it all cool down and then topped up back to 1 bar, and everything seems normal, but as it's fairly new I'm wondering if it's worth getting it checked over?
(Not my boiler but my mum's, installed a couple of years ago. A fault at the electrical substation caused the voltage to fall to about 140V for a few hours, and unfortunately the boiler fired up to top up its hot water side.)
No, it shouldnt cause any lasting damage, that’s why the overheat stat is there, to protect against overheating.
Call the power distributor and explain the situation. If it does cause a problem then at least they're aware. Get names/confirmation/reference number, whatever.
They aren't usually liable for a power cut, but this is a fluctuation that they're responsible for