Schematic Wiring Diagram - Saunier Duval THEMA C 23 Installation And Servicing Instructions

SCHEMATIC WIRING DIAGRAM

X24
T
Bdis.
N
L
b1
b3
3.05
3.09
P
Bdis = Push-button box
P = Pump
P2 = Domestic temperature adjuster
K11 = Flue safety device
SW3 = Microswitch
K4 = Overheat thermostat
K5 = Loss of water switch
EV1 = Gas valve
J1 = Romm thermostat connection
TA = Room thermostat
X24 = Thermocouple and solenoid
CTN = Domestic thermistor
TRA = Transformer
K16 = High limit thermostat
AQ = Boiler thermostat
SW1 = Summer/winter switch
Diagram 29
FAULT FINDING
Before fault finding, check :
Inlet gas pressure = 20 mbar
Electrical supply = 240V - 50 Hz
Central heating system is pressurised at 1 - 1,5 bar
Overheat thermostat on RHS of heat exchanger has
not tripped. Reset if necessary.
Flue safety device on draught diverter has not
tripped. Reset if necessary.
Carry out electrical system checks i.e. earth continu-
ity, resistance to earth, short circuit and polarity with
a suitable meter.
Note: These must be repeated after any servicing or
fault finding. Ensure that all external controls are cor-
rectly wired and calling for heat.
The fault finding charts will enable the majority of faults
to be diagnosed. To use the charts effectively, it is
18
K4
TRA
1.11
1.12
1.07
1.09
R1
1.10
1.04
4.1
4.2
4.5
4.3
5.12 5.01
P2
SW1
2.01
2.02
2.03
2.04
K5
2.05
2.10
2.11
T° K16
2.6
2.8
2.12
2.9
3.01
3.02
3.06
3.03
3.08
5.3 5.4 5.5 5.2
11 21
AQ
T
14 12 22
necessary to determine exactly which aspects of the
boiler are working correctly and which are not.
For example:
If the domestic hot water works correctly but the heat-
ing doesn't, refer to chart No. 1.
If heating works correctly but the hot water doesn't,
refer to chart No. 3.
IMPORTANT: Always adopt a logical, step by step pro-
cedure starting at the beginning of the appropriate
fault finding chart.
WARNING. Always isolate the boiler from the electri-
cal supply before carrying out any electrical replace-
ment work.
Always check for gas soundness after any service
work.
T°
K11
TA
J1
EV1
Ra
CTN
SW3