Worcester 35CDi User Manual

Supplied By www.heating spares.co Tel. 0161 620 6677
31
Red diode is
damaged. Replace
control board.
(Section 15.4.11)
Replace control board.
(Section 15.4.11).
With a hot water tap
fully open, does the
boiler ignite and
appear to run
normally in hot water
mode?
Remove multiway
connector from board
position ST16. With
tap still open is there
continuity across
contacts 19 and 20
(2 pink wires)?
Separate the 2 way in-line
connector to flowswitch
(fitted to boiler side
panel). With tap still open,
is there continuity across
the two terminals still
fixed to side panel? Take
care not to damage
terminals
Replace
Flow Switch
Repair or replace
wiring/harness
FAIL POINT E
No No
No
Yes Yes
Yes
Boiler is running in
“Autofrost stat” mode.
See Section 17.
Is the boiler in a very
cold environment (less
than 5°C)?
Replace control board
(Section 15.4.11 )
Note: A wet board
could cause this fault
FAIL POINT F
No
Yes
Is the boiler fully
water pressurised and
is all air vented?
Rectify fault.
Replace control board
(Section15.4.11 )
FAIL POINT G “Primary Overheat”
No
Replace CH pump
(Section 15.4.20)
or replace cable
Remove pump
connector ST15 from
control board and
retsart boiler in CH
mode. Is there mains
230V pump output
from board
No
Is there mains 230V
across pins 1 & 2 of
terminal X3 of pump
relay PCB?
No
Separate 6 way in-line
connector and check
continuity across
terminals of orange
wires (which run to
back of boiler). TAKE
CARE NOT TO
DAMAGE TERMINAL.
Is there continuity?
No
Is there mains 230V
across pins 1 & 2 of
terminal X2 of pump
relay PCB?
No
Check connections
and wiring back to
connector ST23 on
main board
No
Replace control board.
(Section15.4.11 )
No
Repair or replace
thermostat or orange
wires to thermostat
No
Re -fix sensor to pipe
No
No
Create a central
heating demand. Does
the CH pump run?
Yes
Create a DHW
demand. Does the
DHW pump run?
Yes
Remove multiway
connector from board
position ST16. Is there
continuity across
contacts 5 & 6 (two
orange wires)?
Yes
Yes
Replace DHW pump
(Section 15.4.20 )
or replace cable
Yes
Remove inner casing
cover and inspect the
primary sensor (left of
heaty exchanger). Is it
correctly fixed to
pipe?
Yes
Is there 22-26V dc
across pins 1 & 2 of
terminal X1 of pump
relay PCB?
Yes
Replace pump relay
PCB (Section15.4.13 )
Yes
Repair or replace main
harness
Yes
Replace control board
(Section15.4.11 )
Yes

Worcester 35CDi Specifications

General

Model	35CDi
Output	35kW
ERP Rating	A
Domestic Hot Water Output	35kW
Max Working Pressure	3 bar
Fuel Type	Natural Gas