Technical data

15.0 Fault Finding
48
240 V at A ?
Ensure that mains is
securely connected to
incoming plug and that
wiring from electrical filter
to boiler 8-way terminal
block is OK.
240 V at B ?
Check wiring from boiler
8-way terminal block to
PCB is OK.
Main PCB Fuse OK ?
Check for shorts on
Pump, Diverter Valve,
Fan and Gas Valve,
then replace fuse.
240 V at C ?
Replace Main PCB.
24Vac at D ?
Replace Transformer.
5Vdc at E ?
Replace Main PCB.
YES
YES
YES
YES
YES
YES
NO
NO
NO
NO
NO
NO
Replace Display PCB.
No Display
Mains Input
Transformer
Burner On
&
Fault Neons
Pump
Diverter Valve
Gas Valve
Modem PCB
Room Thermostat
Flow &
Return
Thermistors
Overheat
Thermostats
&
Flow Switches
&
Condensate Trap
Room Control
Display PCB
Fan
A
D
C
B
E
Prog
1
2
1
2
L
N
Prog R/S R/S
Extra
Pump