Bosch Worcester 28si was not heating water

[Happychappy1971]

Hi all just got back from holiday so boiler thermostat was turned down to 14c while away. After 30 minutes noticed radiators was just Luke warm ,looked at boiler and red tap light was flashing. Turned boiler off topped water pressure up a bit as was bit lower than normal. Still after a while the tap light was flashing red and radiators not that hot. Tried turning kitchen hot tap on and off few times didnt get that hot . Anyway powered down boiler and back up now it seems to be heating radiators hot as normal. Just curious what could have been the fault ? Stuck pressure sensor or stuck diverted valve ? . All seems ok at the moment hoping it was just because it’s been off for while but love to know what causes those symptoms many thanks in advance Paul .

 

[CBW]

Sounds like could have been stuck diverter or flow sensor

 

[Happychappy1971]

Hi the heating is going ok now but when we turn the hot tap on it starts to get hot then the red tap light flickers and you can hear the burners going down and the water goes cold. If I turn the boiler off then on again the hot water starts heat again then goes cold again. Last night the tap was flickering when the central heating was not getting hot but that’s ok now just the hot water . So would the prob be the diverted valve ?. Would it have got stuck not working for a week when we were away ?.

 

[Happychappy1971]

Hi all just thought I would report the fault in case anyone else suffers . I noticed the boiler flue above a roof had a bird stuck head first in it just tail sticking out. It must have been that when hot water demand was high it was detecting restriction in the flue.