Anyone knows anything about electric boiler in Hestia house.. Or plumber .
Mine suddenly stopped heating and unable to press boost button as well, after I found out the main switch had turned off and which I turned it on again.
I don't know if this is a coincidence but this topic came up earlier in the week in the Hestia House mailing list
Anyway, it's likely that you have a Dedicated Pressure Systems (DPS) Pandora Heat Bank System. That company went bust but has been taken over. If you go to the original website www.heatweb.com, on the right hand side, there is a link to a plumbing company called Domestic Plumbing Service http://domesticplumbingservices.com/
I haven't used them myself but one of the posters said she used successfully when she first moved in and had a problem.