FAULT FINDING
mini HE
--- Installation & Servicing
47
69 MAIN CONTROL P.C.B.
OPTICAL INFORMATION
The main control p.c.b. is provided with three lamps (L.E.D.
indicators) A that give optical information during the normal
operation of the boiler or for service and fault fiinding
purpose.
Normal operation
The green lamp on the left is directly visible on the control
panel fascia and it gives information during the normal
operation of the boiler. The other two lamps are normally
switched off.
The following table gives the relationship between the visible
lamp indication and its meaning.
Boiler in stand---by condition.
(function control in
position).
Anti---freeze system active.
A short pulse every 4 seconds
(function control in
position).
Anti---freeze system active.
Boiler ON condition
(function control in
or
position)
1 second ON 1 second OFF
(function control in
or
position)
Very fast pulses (4 per second)
Faulty boiler or irregular
operation as:
--- Empty primary circuit
--- No primary circuit flow
--- Lack of burner ignition
--- Lack of burner ignition
--- Excessive temperature in the
primary circuit.
--- Dip---switch 3 left in the OFF
position
--- Faulty temperature probe
The following table gives a summary of the relationship
between each of the possible lamp combinations and their
meaning.
Normally operating boiler
CH operation
DHW operation
Frost protect operation
DHW operation
Excessive temperature on primary circuit
Faulty CH temperature probe NTC
Faulty DHW temperature probe NTC
Faulty primary circuit
(no water or absence of flow)
Lack of burner ignition (no ignition signal from
the full seqence ignition device)
Ignition gas pressure adjustment
Minimum gas pressure adjustment
Lamp
OFF
Lamp
ON
Flashing lamp, alone
or simultaneously
with an other lamp.
Flashing lamp,
alternate with
another lamp.
70 DIVERTER VALVE ACTUATOR
SPINDLE POSITION
To remove the diverter valve actuator refer to frame 64.
The following illustrations indicate the relationship between
the electric command coming from the main control p.c.b.
and the position of the brass spindle when the boiler operates
in either
DHW mode or CH mode.
In both figures the relationship between the position of the
actuator and the resistance of the motor windings (the motor
must be disconnected from the wiring) is also given.
bn = brown
bu = blue
bk = black
23
0
V
0
V
Spindle
visible
Open circuit
9,4 Kohm
bk
bn
bu
3
1
2
0
V
23
0
V
Spindle fully
retracted
Open circuit
9,4 Kohm
bk
bn
bu
3
1
2
CH mode
DHW mode
FA
U
LT
F
IN
D
IN
G