
FAULT FINDING AND DIAGNOSIS
6 720 804 532 (2012/09)
51
7.1.1
CIRCUIT DIAGRAM
FAN
FS
FR
NP LP
L
N
S
N
L
S
L
R
ST8
ST9
ST17
ST18
ST5
ST4
ST10
Earth
MAINS
SUPPLY
PUMP
SUPPLY
SPARK
TRANSFORMER
FLAME SENSE
ELECTRODE
SPARK
ELECTRODES
OVERHEAT
STAT
FLOW
TURBINE
DIVERTER
VALVE
FLUE
OVERHEAT
STAT
ST1
DIAGNOSTIC
INTERFACE
CODE PLUG
Fuse F1, slow
2.5 A, AC 230 V
ST6
DHW TEMPERATURE
CONTROL
EXTERNAL
FROST STAT
(OPTIONAL)
CH TEMPERATURE
CONTROL
Red
Neutral Supply
230V
EXTERNAL
CONTROLS
OPTION
WORCESTER 24V CONTROLS
OPTION, PLUG IN POINT
(under blanking cover on fascia)
Live Supply
Live Return
Neutral
Live
Orange
Blue
Yellow
Green
Black
Colour sequence †
Purple
Purple
Blue
Blue
Red
Red
Yellow
Yellow
Black
Yellow
Red
Orange
Orange
7
8
9
*
PRE WIRED LINK
*
*
EMS BUS contacts
(for FX controls)
Outside sensor
(FW 100)
B
B
4
2
1
A
F
Wall plate contacts
(for FX controls)
B
B
Colour sequenc
e †
PUMP
Green
GAS
VALVE
SAFETY
SOLENOID
SAFETY
SOLENOID
† Fan wiring:
Live = purple
Neutral = brown
FLOW TEMP.
SENSOR (NTC)
DHW TEMP.
SENSOR (NTC)
S11
230V~
6720804530-09.2Wo
ST19