54
Installation and Servicing
Section 4 - Fault Finding
FAUL
T FINDING
4.12 NO DHW OPERATION
COMBI
HEA
T / SYSTEM
SL1
IN OUT
IN OUT
SL2
OPTIONAL
FROST STAT
ROOM
STAT/
TIMER L N
MAINS IN
UIN
230010 A01
L N
MAINS IN
L
N
Is the Cylinder Stat calling for heat?
YES
NO
Adjust cylinder stat
Is DHW timer on?
YES
NO
Switch timer on
Is OFF shown under Tap symbol?
NO
YES
Press mode button until OFF is not shown under the
Tap symbol
Is there 230 V at SL2 IN
NO
Check system controls and wiring
Is an Outside Sensor connected?
YES
YES
Check wiring from terminal strip to PCB
Ensure that 230 V is not connected to SL1 (IN)
YES
4.13 NO DISPLAY
Is there 230Vac to the boiler at L and N?
YES
NO
Supply power to the boiler
Is the wiring from the terminal block to the PCB
connected securely?
YES
NO
Connect the wiring from the terminal block to the
PCB securely.
Replace the PCB?
OPEN THERM./
WEATHER COMP.
B