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19
6.6
D.H.W. MODE - FAULT FINDING
Start from cold - rotary switch set to SUMMER position, D.H.W. thermostat set to maximum, and all D.H.W. taps OFF.
NOTE:
When commissioning the boiler, please check the polarity in case the pump and the fan are running but the burner does
not fire.
Is there power
at the external
socket?
Make
power
available
Does
the pump
start?
Does
the fan
start?
Set right ignition
probe
Is there a spark
at the ignition elec-
trode?
Is fuse
at mains
plug OK?
Replace
fuse in
mains plug
Is smoke
pressure switch
connected right?
Check smoke
pressure
switch and fan
connection
Is there continuity
between
ignition probe
and ground?
Make it
free to
rotate
Is there power
at L and N
terminals?
Check wire
connections
to L and N
terminals
Is there
voltage available
at the pump?
Is smoke
pressure switch
closed?
Replace the smoke
pressure switch
Is the smoke
pressure switch
contact in open
position?
Check gap
between ignition
electrode and
hood. Check the
electrode lead
and fit are not
damaged. Does it
now spark?
Is pump
shaft free
to rotate?
Open any
D.H.W. tap
to give flow
2.8 l/min.
Can you
get the desired
flow at the
D.H.W. taps?
Are microswitches
of divertor valve
operated?
Is limit
thermostat
calling for heat?
Replace the
limit thermostat
Replace the
pump
Replace the
divertor valve
Is fuse
F1 OK?
Is sensor
disconnected?
Connect
the sensor
Check pump
connection
Clean or replace
filter at inlet of
divertor valve
Set right
the contacts
Replace
fuse F1
Is there
continuity
between
power terminals
of PCB control
board and PCB
ignition?
Is sensor OK?
Replace
sensor
Is there 230V AC
available between
11 and 4
terminals and
between
11 and 10
terminals of PCB
ignition?
Replace the
PCB control
board
Is there 230V AC
available at
the fan terminal?
Replace
the fan
Has the PCB
ignition
locked-out after
10 seconds
without flame
at the burner?
Has the PCB
ignition
locked-out after 10
seconds
with flame
at the burner
before lock?
Can the burner
pressure be
reduced by the
D.H.W. ajuster?
Does the burner
pressure reduce
as the temperature
rises towards max.?
Check:
1) Limit
thermostat
2) D.H.W.
thermistor
3) PCB control
board
Is the burner
pressure set to
the maximum?
Check the gap
between the
ionisation probe
and hood.
Check if the
electrode lead
and fit are not
damaged.
Does it now
detect the flame?
Replace the
D.H.W. thermistor
Does
the boiler
swich OFF
before achieving
the temperature?
Is there a
voltage at the
modulator?
Is the gas
available?
Open the
gas cock
Replace the
modulator
Is the limit
thermostat OK?
Replace the
limit thermostat
Turn
the plug
Boiler is
satisfactory
Is there
continuity between
PCB control
board and
the gas valve?
Replace the
gas valve
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Set right
the connection
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