Boiler not igniting when asking for dhw , neon B flashing every 5 seconds, so no fault indicated, please help! ( ps heating working ok )
The lights flashing mean low pressure as indicated by the gauge on zero, Raise the pressure to the green area on the gauge by opening the filling loop valves and then turn them off. On this model the filling loop is under the plastic tray at the bottom of the boiler, it is a silver flexible pipe about 12 inches long with valves at each end.
Its the diaphragm or hot water flow switch. Usually the switch on this model. The switch is easy to change, costs about ?30, the diaphragm would need an engineer to replace.
first thing you have proberly paid out more than it would cost you to have insured you system for a year or got a honest corgi engineer out to solve your problem but all may not be lost just drain your boiler and check the pressure in the expansion vessel approx 1/2 bar if not pump it up also change the aav if this does cure your problem then call a engineer depending about ?40.00 to ?80.00 a hour .most faults found in about 1/2 hr.
