The boiler is designed to operate at one bar pressure when cold. The sealed system has been charged (twice) but the pressure drops to zero over a couple of days although heating and hot water seem to work normally. Is it harmful to run the system as it is? There is no evidence of a water leak anywhere as far as I can tell

Stuart, September 2012

If pressure drops than there a leak ,check over flow pipe any water out side it will work but with no water boiler will to lockout

ltd, September 2012