Worcester 24ijunior Installation And Servicing Instructions page 42

No
Is the boiler in a very
cold environment (less
than 5°C)?
Yes
Boiler is running in
"Autofrost stat" mode.
See Section 17.
Hot water
temperature always
too hot during a
demand (not
regulating).
No
Does the problem
occur in CH mode
only?
Yes
It is not possible to
easily isolate the fault.
The most likely causes
are control board (fail),
heat exchanger
(blocked) or
gas valve (sticking).
Replace control board.
Note: A damp board
could cause this fault.
Hot water sensor
could be off or poorly
fixed to pipe.
Repair or replace.
Problem occurs in the
No
HW mode only.
Check flow sensor:
with boiler cool,
slowly open a HW tap.
Does the boiler ignite
with a flow of about
3 l/min?
(Check using a
measuring jug and
stop watch i.e 500ml
in 10 sec.
Yes
42
Turbine sticking or
seized.
Replace the turbine.