Does anyone know if the (Elm) Le Blanc 420 boiler has a diverter valve (or not). A heating engineer has changed a thermostat and a solenoid but domestic hot water is still running cool. I suggested the diverter valve, as it's the classic symptom of a holed diaphragm but the engineer from British Gas (!) maintains that this boiler doesn't have one. If he's correct how is the water switched from CH to DHW?
tia Hugh