Sime Format System 25 HE Installation And Servicing Instructions page 19

5.5 C.H. MODE - FAULT FINDING
Start from cold Rotary switch set to WINTER position.
Room thermostat (if fitted) calling for heat.
C.H. thermostat set to maximum position.
Clock in the on position (if fitted).
No
Is there power Make
at the external power
socket? available
Yes
Is fuse
Yes
at mains
plug OK?
No
Replace fuse in
mains plug
Put a jumper on
Replace
the room thermo-
the fuse
stat connection
No No
Yes
Is there a jumper
Is fuse
on the room
thermostat 0,6 A OK?
connection?
Yes
Check pump
connection
Fit correctly the
ignition electrode
Does the boiler
lock-out without
No
starting the
burner?
The gap between
ignition electrode
and hood
is correct?
Yes
Yes
Check for continu- No
Is there a spark
ity between ignition
at the ignition
electrode and igni-
electrode?
tion transformer
Yes
No
Is the gas
Check the
available?
gas supply
Yes
No
Check the
Is there voltage at
connection on
the gas valve?
the fan PCB
Yes
Replace the
gas valve
NOTE:
After completing fault finding reset the room thermostat (if fitted) to the required setting. If the appliance will not function check the wiring
to the clock and if necessary, replace the clock.
Yes
Does Turn the clock
the pump in the right
start? position
No
No
Is the clock in
Replace
the correct
the clock
band time?
Yes
No
Make it free to
rotate
Check the
time clock does
his contacts
open and close
when the clock
turns?
Is pump shaft
free to rotate?
Yes
No
Yes
Is there voltage
Replace
available
the pump
to the pump?
No No
The ignition of the
burner is noisy
The boiler
lock-out
starting
the burner
Check the settings
of the gas valve
and "POT. ACC."
trimmer
Yes
reverse
polarity between
phase and neutral
Yes
Does
the fan
start?
No
Is there voltage
available
to the fan?
No
Yes
Replace
the fan
No
Check the
power supply
cable
Yes
No
Yes
No
Does the boiler
remain in
pre-purge mode?
Yes
No
Is limit
Replace the
thermostat
limit thermostat
calling for heat?
Yes
Yes
Is the micro-switch Loose the screw
on the diverter on the flow
valve locked? switch cover
No
Yes
Does the
micro-switch
Check the
operate correctly?
connections of:
limit thermostat
No
and
flow switch
in the PCB
Replace the
control board
microswitch
No
Check:
Does the fan
speed decrease
2) C.H.
reducing the flow
thermistor
temperature
setting on
3) PCB control
the C.H. knob?
board
Yes
No
Does the
boiler switch
OFF before
achieving the
temperature?
Yes
Boiler is
satisfactory
17