Bosch 14/19CBI - Manual (Page 39)

39
FAIL POINT F
Delivered primary water
temperature always too hot.
(Over 85°C)
Delivered primary water
temperature appears too
low with control knob set to
maximum.
(Less than 75°C)
Such a fault is likely to be caused
by one or more of the following:
Low gas pressure
Partially blocked flue
Partially blocked heat exchanger
Blocked/dirty burner
Gas valve sticking
Control board fault
Faulty themister
Replace control board.
Move control knob to lower
setting.
Check thermister
sensor/heat conductive
paste.