Worcester 24CDi Installation And Servicing Instructions

34
Boiler is running in
“Autofrost stat” mode.
See Section 18.
Replace control board.
(Section 16.4.23).
Note: A wet board
could cause this fault.
Is the boiler in a very
cold environment (less
than 5°C)?
Drop down the facia.
Is the gas valve mode
switch in the normal
position?
Turn to normal
position.
FAIL POINT F
No No
Yes Yes
Is the boiler fully
water pressurised and
is all air vented?
Rectify fault.
FAIL POINT G “Primary Overheat”
No
Re-fix sensor to pipe.
No
No
Repair or replace
pump.
(Section 16.4.14).
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 primary heat
exchanger
Replace overheat
thermostat or check
wiring to it
Yes
Replace CH sensor
(Section 16.4.12
No
Does the burner
switch off when the
primary temperature
reaches 94°C
Yes
Yes

Worcester 24CDi Specifications

General

Model	24CDi
Output	24 kW
Efficiency Rating	A
Max Working Pressure	3 bar
Central Heating Flow Temperature Range	30 - 80 °C
Fuel Type	Natural Gas
Mounting	Wall Mounted