FAULT FINDING
Mini
Installation & Servicing
49
Continued from page
48 of fault finding
Remove the
motor
assembly, with
230V at the
connections is
the spindle fully
retracted? Refer
to frame 68.
Dismantle the
DHW detector
valve and clean.
Refer to frame 60.
Reassemble.
Does the DHW
water become
hot?
Continued on page
54 of fault finding
no
yes
yes
yes
yes
yes
yes
yes
yes
yes
yes
yes
yes
yes
no
no
no
no
no
no
no
no
no
no
no
no
With the boiler and
heating circuit warm
does the burner
pressure reduce if the
heating temperature
setting is reduced to
minimum?
Is there between 0V dc
and 16V dc at the
connections on the
modulating coil?
(0=min, 16=max)
Repair or replace
faulty wiring
Is the continuity of the
modulator harness
O.K?
Repair faulty gas
valve
Repair faulty PCB
When a DHW tap is
opened and the DHW
temperature is set to
maximum, does the
water become hot?
Is the boiler mode
setting correct?
(Refer to frame 56)
Follow the instruction
“Boiler mode setting”
(Refer to frame 56)
Is the red LED
illuminated on DHW
flow sensor?
Is there 5V dc between
Red and Blue on
connecting harness?
Is the harness
continuity O.K?
Repair or
replace
faulty
wiring
Repair faulty PCB
Repair or
replace
faulty
wiring
Is there 230V
ac between
Blue and
Black at the
3---way valve
connection?
Is the
continuity of
the 3---way
valve
harness
O.K?
Repair faulty
PCB
Replace
faulty valve
body
assembly
Replace
faulty motor
assembly
Replace the
sensor. Is
red LED
illuminated?
Faulty
sensor
now
replaced
Repair or
replace
faulty DHW
detector
valve
Combination
boilers only
Continued below
yes
Is the burner pressure
within min and max
value* with the boiler
running?
no
Adjust burner pressure.
Refer to frame 29.
* see Table 2 at page 4 for the correct value
FA
UL
T
F
IND
ING
