Fault Finding - Baxi Solo 3 PFL 30 Installation & Servicing Instructions Manual

Before starting FAULT FINDING carry out
preliminary electrical system checks i.e. Earth
Continuity, Polarity, Short Circuit and
Resistance to Earth.
START
Ensure external controls
are calling for heat
YES
Is
there mains voltage at
P/L input ?
YES
Is
there mains voltage at
Pump L output ?
Check external wiring
NO
YES
Check fuse on circuit
board
Change PCB
No continuity across
fuse, change fuse
YES
Check pump wiring
YES
Investigate
pump
NO
Replace thermostat
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YES
Does pump run ?
NO
Is
"Boiler On"
light on ?
NO
YES
Is
there mains voltage at
S/L input ?
NO
YES
Change
potentiometer
Note: This can occur if
the boiler has overheated
Reset by turning control
knob OFF, wait 10
seconds then turn ON
Does
lockout light
go out ?
NO
Is there
continuity across the
overheat thermostat ?
11.0

Fault Finding

YES
Does fan run ?
NO
Is
lockout light
on ?
NO
NO
Is
"Fan On"
light on ?
NO
Check control knob
is turned on
Check that the wires are
connected to the
thermostat sensor
YES
Check that the fan &
pressure switch plug is
connected
Check continuity across
sensor
(1 M OHM at 20 o C)
No continuity - change
sensor
Check continuity across
pilot solenoid (1.5 K
OHM)
No continuity - change
pilot solenoid
Check Potentiometer
(see table)
NO
Replace harness
Is
there a clear constant
spark at the electrode
?
NO
Is
"Pilot On"
light on ?
YES
Check & clean electrode.
Check gap & lead
YES
Change PCB
Note: Under cold
conditions fan run up time
may exceed
1 min
Check pressure switch
pipes for leaking or
blockage
Is there
continuity between C
& NC terminals on the
pressure
switch ?
YES
NO
Replace pressure
switch
Replace fan
Is
there mains at
the fan
connection ?
YES
Replace fan
YES