Pressure was shooting upto 3.5 bar solved by replacing expansion vessel with VAREM external 8 litre unit and pressure goes from 1.2 to 1.5 bar when hot.
But now the CH temperature overshoots setpoint by over 10 degrees. Radiators seem to be getting hot fairly quickly. Then when burner cuts out temperature drops very rapidly. occasionally the boiler fails to fire up. Hear the pump running but only way to get it to fire seems to be to switch power off for few minutes and back on again. No error messages on display. Any pointers please?
But now the CH temperature overshoots setpoint by over 10 degrees. Radiators seem to be getting hot fairly quickly. Then when burner cuts out temperature drops very rapidly. occasionally the boiler fails to fire up. Hear the pump running but only way to get it to fire seems to be to switch power off for few minutes and back on again. No error messages on display. Any pointers please?