What would you hazard a guess at my CH system volume to be? Std 3 bed semi, 7 rads of which (1 double, 1 tiny, 1 medium), 15mm pipework except flow & return between up & downstairs (ie 2 * 2m * 22mm diam). No cylinder, converting to combi. It's to determine if the expansion vessel is adequate. 100 litres is the make or break.
Thanks, Mike W