On Sat, 14 Nov 2020 08:46:20 +0000, Brian Gaff \(Sofa\) wrote:

Don't you think that with all the innovations in boilers and the
considerable logic now possible at a relatively low cost, that they do
not build in sensors that do the topping up automatically. This would
also serve as a leak detector as if it needed topping up a lot there has
to be a problem.
Brian

In one of my houses in the past, I had a coal fire with a back boiler.
Over the 20 odd years I was there, I never knew how the boiler got it's
water supply, but it always served up nearly boiling water with no
servicing.