In article ,
Fredxx wrote:
A simple system boiler has a variable speed fan and a modulating gas
valve. No other moving parts.

Pump?

Ok I confess to meaning a heat only boiler such as:
https://www.baxi.co.uk/our-boilers/heat-only-boilers

These don't have a pump, or any of the other over priced paraphernalia
that can go wrong.

I'd call that a basic electric boiler. And am surprised you can still buy
them. Given you need sophisticated management to get the best efficiency.

BTW, why do you think an external pump is not going to be an 'over priced
paraphernalia that can go wrong'?

--
*Never test the depth of the water with both feet.*

Dave Plowman London SW
To e-mail, change noise into sound.