Why does the pressure keep dropping on my combi boiler?If the pressure keeps dropping on your combi boiler, it means it is losing water somewhere. There are three common places to lose water: . The radiator valves. This is an easy one to check, run your hand around your radiator valves ( when turned off and with pressure in the boiler). If any of the valves are wet, then there is the problem. . The expansion vessel. The easiest way to check this is to check for water discharge from ...
