Worcester Boiler, very common to find this fault, the glass sight glass and rubber gasket perish over time, this causes the combustion products to leak (spilliage)
Notice the dark patch top left?
Thats spilliage and Carbon Monoxide leaking
Boiler Servicing is IMPORTANT
Worcester have now upgraded this electrode so that it does not have the fight glass!, if you still have this call us to upgrade it
Boiler Losing Pressure?
Common to find Diverter Valves and Automatic Air Vents Leaking
Auto Air vent Leaking
Auto Air Vent
To many times I arrive to find this has or was leaking, usually a lazy engineer will just turn the black screw to shut off the leak, thus rendering the air vent useless, get a professional engineer in who takes pride in their work