Fault
Fault
Possible cause
code
A21
Card parameter fault
Wrong card parameter setting
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
F37
Water pressure switch damaged
pressure
or not connected
Probe damaged or wiring shorted
F39
External probe fault
Probe disconnected after activat-
ing the sliding temperature
Delivery sensor or DHW sensor
A41
Sensor positioning
detached from the pipe
F42
Heating sensor fault
Sensor damaged
No system H
F43
Exchanger protection trips.
Air in the system
Modulating Operator wiring dis-
connected
F50
Gas valve fault
Faulty gas valve
5. TECHNICAL DATA AND CHARACTERISTICS
Table. 3 - Key of figures cap. 5
7 Gas inlet
8 Domestic hot water outlet
9 Cold water inlet
10 System delivery
11 System return
14 Safety valve
19 Combustion chamber
20 Burner assembly
21 Main nozzle
22 Burner
26 Combustion chamber insulation
27 Copper exchanger for heating and hot water
32 Heating circulating pump
36 Automatic air vent
38 Flowswitch
32
EN
Cure
Check the card parameter and modify
it if necessary
Check the card parameter and modify
it if necessary
Check the card parameter and modify
it if necessary
Check the electrical system
Check the electrical system
Fill the system
Check the sensor
Check the wiring or replace the sen-
sor
Reconnect the external sensor or dis-
able the sliding temperature
Check the correct positioning and
operation of the sensors
Replace the sensor
O circulation
Check the circulating pump
2
Vent the system
Check the wiring
Check the gas valve and replace it if
necessary
42 DHW temperature probe
44 Gas valve
56 Expansion tank
72 Room thermostat
74 System filling cock
78 Anti-backflow device
81 Ignition and detection electrode
114 Water pressure switch
126 Fume thermostat
138 External probe (optional)
139 Remote timer control
278 Double sensor (Safety + Heating)
290 Antiwind grille
340 Bypass pipe
cod. 3540Z952 - Rev. 00 - ediz. 10/2013
DOMItech C 24 - 32 D
5.1 General view and main components
278
81
20
21
22
340
42
290
10
8
44 7
fig. 13 - General view DOMItech C 24 D
56
278
81
20
21
22
340
42
290
10
8 44 7
fig. 14 - DOMItech C 24 D
126
56
78
27
19
26
14
36
114
74
9
38
11 32
126
78
27
19
26
14
36
114
38
9
74
11 32