35
Boiler is running in
“Autofrost stat” mode.
See Section 17.
Replace control board.
(Section 15.4.10).
Note:
A damp board
could cause this fault.
Is the boiler in a very
cold environment (less
than 5°C)?
FAIL POINT F
No
Yes
Is the boiler fully
water pressurised and
is all air vented?
Rectify fault.
FAIL POINT G “Primary Ov
erhea
t”
No
Re-fix sensor to pipe.
No
No
Repair or replace
pump.
(Section 15.4.18).
No
Reset the controls and
restart the boiler.
Does the pump run?
Yes
Remove inner casing
cover and inspect the
primary sensor (left of
heat exchanger).
Is it correctly fixed to
pipe?
Yes
Remove the multiway
connector from board
position ST16.
Is there a short circuit
across contacts 5 & 6?
Fault caused by control
board or heat
exchanger
Replace overheat
thermostat or check
wiring to it
Yes
Yes
Содержание 28Si
Страница 29: ...29 ...
Страница 56: ...TO REPLACE THE PROGRAMMER Follow the preceding instructions 3 Programmer connection Fig 1 ST5 ...
Страница 57: ...4 OFF TWICE ONCE ON ...