On Wednesday, 28 October 2020 19:07:06 UTC, David WE Roberts (Google) wrote:
If there were more than a certain number of radiators it required an
additional expansion vessel to be fitted (beyond the one which came inside
the boiler).
The plumber had never heard of this before.
[Was also indecently amused that anyone would bother to read the manual.]


Heaven forbid he would actually calculate the volume of water in the system

Owain