Worcester 24CDi Installation And Servicing Instructions

36
Remove multiway
connector from board
position ST16. Test
resistance across
contacts 17 and 18
(yellow wires). Is it
between 1 kohm and
30 kohm?
Test resistance across
contacts 12 and 13
(red wires). Is it
between 1 kohm and
30 kohm?
Test resistance across
contacts 7 and 8
(brown wires) and 9
and 10 (violet wires).
Are both readings
below 100 ohms?
Replace control board.
(Section 16.4.23).
Replace gas valve.
(Section 16.4.11).
Remove both brown
connectors from gas
valve. (First remove
pressure switch
bracket). Is there
continuity from
brown and violet
wires to the multiway
connector?
Check or replace CH
sensor.
(Section 16.4.12).
Is there continuity
from contacts 17 and
18 to DHW sensor?
Check or replace
DHW sensor.
(Section 16.4.13).
Is there continuity
from contacts 12 and
13 to CH sensor?
Repair or replace
harness.
Repair or replace
harness.
Repair or replace
harness.
Is the multiway
connector at board
position ST16 pushed
fully home on to the
board?
Push fully home.
FAIL POINT I “Sensor Fault”
No
No
No
No
No
No
No
Yes
Yes
Yes
Yes
Yes
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