New GlowWorm 30CXI combi boiler with pressure drop problems since installation late 2006.
Day one ....New Diverter Valve fitted before it would run.
Pressure dropped slowly in first few months. No loss with CH off.
Under concrete floor system isolated and checked with 5 pressure (Rothenburger pump) 24 hours - No loss shown.
New pressure relief valve and pressure sensor fitted by Glow Worm.
Glow Worm replaced pressure vessel as holding no air when checked.
Checked system by isolating boiler from CH for 17 hours - no loss in pressure when turned back on.
Pressure continues to drop to switch off within 3 days -after setting to 1.5
Is there any way of being 100% sure of no leak in piping - Corgi reg CH Plumber and Glow Worm so far no answer.