4.4 Troubleshooting
Diagnostics
The boiler has an advanced self-diagnosis system. In case of a boiler fault, the display
will flash together with the fault symbol (detail 11 - fig. 1) indicating the fault code.
There are faults that cause permanent shutdowns (marked with the letter "A"): to restore
operation, press the RESET button (detail 6 - fig. 1) for 1 second or RESET on the op-
tional remote timer control if installed. At this point the display will show "d4" for about
30 seconds or "d5" for about 5 minutes which indicates the waiting time after which the
boiler will resume normal operation. if the boiler fails to restart, it is necessary to eliminate
the fault.
Other faults cause temporary shutdowns (marked with the letter "F") which are automat-
ically reset as soon as the value returns within the boiler's normal working range.
List of faults
Table. 10
Code
Fault
Possible cause
fault
No gas
Ignition/detection electrode fault
A01
No burner ignition
Faulty gas valve
Gas valve wiring disconnected
Ignition power too low
Electrode fault
Flame present signal with
A02
burner off
Card fault
Heating sensor damaged
Overtemperature protection
A03
activation
No water circulation in the system
Air in the system
F04
Card parameter fault
Wrong card parameter setting
Card parameter fault
Wrong card parameter setting
Wiring disconnected
F05
Fan fault
Defective fan
Card fault
Low pressure in the gas system
No flame after the ignition
A06
phase
Burner minimum pressure setting
F07
Card parameter fault
Wrong card parameter setting
Wiring disconnected
A09
Gas valve fault
Faulty gas valve
Sensor damaged
F10
Delivery sensor 1 fault
Wiring shorted
Wiring disconnected
Sensor damaged
F11
DHW sensor fault
Wiring shorted
Wiring disconnected
Sensor damaged
F14
Delivery sensor 2 fault
Wiring shorted
Wiring disconnected
Wiring disconnected
A16
Gas valve fault
Faulty gas valve
Fan fault
Faulty baffle
F20
Combustion control fault
Flue not correctly sized or
obstructed
Fault F20 generated 6 times in the
A21
Poor combustion fault
last 10 minutes
A23
Card parameter fault
Wrong card parameter setting
A24
Card parameter fault
Wrong card parameter setting
F34
Supply voltage under 180V.
Electric mains trouble
F35
Faulty mains frequency
Electric mains trouble
Pressure too low
Incorrect system water pres-
F37
Water pressure switch damaged or
sure
not connected
60
EN
Code
fault
F39
A41
F42
F43
F50
A51
Cure
Check the regular gas flow to the
5. TECHNICAL DATA AND CHARACTERISTICS
boiler and that the air has been elim-
inated from the pipes
Check the wiring of the electrode
Table. 11- Legend, fig. 26, fig. 27 and fig. 28
and that it is correctly positioned and
5 Sealed chamber
free of any deposits
7 Gas inlet - Ø 1/2"
Check the gas valve and replace it if
necessary
8 DHW outlet - Ø 1/2"
Check the wiring
9 DHW inlet - Ø 1/2"
Adjust the ignition power
10 System delivery - Ø 3/4"
Check the ionisation electrode wiring
11 System return - Ø 3/4"
Check the card
14 Pressure relief valve
Check the correct positioning and
16 Fan
operation of the heating sensor
19 Combustion chamber
Check the circulating pump
22 Burner
Vent the system
27 Copper exchanger for heating and DHW
Check the card parameter and mod-
29 Fume outlet collar
ify it if necessary
32 Heating circulating pump
Check the card parameter and mod-
ify it if necessary
36 Automatic air vent
Check the wiring
37 Cold water inlet filter
Check the fan
42 DHW temperature sensor
Check the card
Check the gas pressure
Check the pressures
Check the card parameter and mod-
ify it if necessary
Check the wiring
Check the gas valve and replace it if
necessary
Check the wiring or replace the sen-
sor
Check the wiring or replace the sen-
sor
Check the wiring or replace the sen-
sor
Check the wiring
Check the gas valve and replace it if
necessary
Check the fan and fan wiring
Check the baffle and replace it if
necessary
Check the flue
See fault F20
Check the card parameter and mod-
ify it if necessary
Check the card parameter and mod-
ify it if necessary
Check the electrical system
Check the electrical system
Fill the system
Check the sensor
cod. 3541N242 - Rev. 02 - 04/2018
DIVACONDENS F D
Fault
Possible cause
Probe damaged or wiring shorted
External probe fault
Probe disconnected after activating
the sliding temperature
Delivery sensor or DHW sensor
Sensor positioning
detached from the pipe
Heating sensor fault
Sensor damaged
No H
O system circulation
2
Exchanger protection trips.
Air in the system
Modulating Operator wiring discon-
nected
Gas valve fault
Faulty gas valve
Poor combustion fault
Inlet/exhaust flue obstruction
Cure
Check the wiring or replace the sen-
sor
Reconnect the external sensor or
disable the sliding temperature
Check the correct positioning and
operation of the sensors
Replace the sensor
Check the circulating pump
Vent the system
Check the wiring
Check the gas valve and replace it if
necessary
Check the flue
44 Gas valve
56 Expansion vessel
74 System filling faucet
81 Ignition and detection electrode
95 Diverter valve
114 Water pressure switch
136 Flowmeter
137 Pressure sensor
191 Contact fume thermostat
193 Trap
194 DHW exchanger
241 Automatic bypass
277 Fume recuperator
278 Double sensor (Safety + heating)