On Friday, 14 February 2020 10:48:49 UTC, Dave Plowman (News) wrote:

My first boiler - a Potterton floor standing BE BF type did need a service
once in a while. Otherwise it would soot up and stop working. I'd guess
modern units burn more cleanly?

I think I read somewhere condensing boilers tend to keep themselves clean thanks to the condensation produced which carries soot away? Could be nonsense.