Unical DUA plus, Installation And User Instruction Manual

Page: 26 / 32

26
Service info
2.8 – FAULT FINDING CHART AND POSSIBLE SOLUTIONS
In case of fault lamp lighting depress the Reset push button and, while kipping it
depressed, look at the error code given by the flashing leds.
Note: The error code is given by the combination of two, three, four of five leds,
flashing on the temperature scale.
SIGNIFICATION OF THE ERROR CODE
Fault on the outer temperature
sensor (if connected)
POSSIBLE SOLUTION
The control of the flow temperature by
the outer sensor is non active. Call
the After Sale Service
BOILER STATUS
This fault does not cause the locking
of the boiler.
SIGNIFICATION OF THE ERROR CODE
Faulty flame control PCB
POSSIBLE SOLUTION
Replace the ignition and/or modulating
PCB
BOILER STATUS
The boiler is in lockout position
SIGNIFICATION OF THE ERROR CODE
Fault on the gas valve modulation
system (coil interrupted)
POSSIBLE SOLUTION
Replace the gas valve modulation
coil, after checking of the harness,
the supply tension and the gas
pressure.
BOILER STATUS
Chaudière fonctionnant à la puissance
mini.
SIGNIFICATION OF THE ERROR CODE
The air pressure switch is faulty or in
short circuit (only for TFS version)
POSSIBLE SOLUTION
Inspect the air pressure switch
operation
BOILER STATUS
The boiler is in lockout position
SIGNIFICATION OF THE ERROR CODE
Too high boiler temperature
POSSIBLE SOLUTION
Make sure the pump is properly
operating and the heat exchanger is
clean inside
BOILER STATUS
The boiler is in lockout position
SIGNIFICATION OF THE ERROR
CODE
Fault on the smoke evacuation
system; after 15 min there is an
automatic reset.
POSSIBLE SOLUTION
For TN version: check the
chimney draught
For TFS version: ascertain the
good operation of the fan and its
air pressure switch.
Depress the Reset button.
BOILER STATUS
The boiler is in lockout position
SIGNIFICATION OF THE ERROR CODE
The water pressure within the
installation is below 0.5 bar
POSSIBLE SOLUTION
Reinstate the water pressure through
the filling valve (accessible also to
the user) and look for possible water
leaks. If the problem is not solved
call the After Sale Service.
BOILER STATUS
The boiler is in lockout position
SIGNIFICATION OF THE ERROR CODE
Probable freezing of the primary heat
exchanger; temperature below 2°C
detected by the SR or SS sensors.
POSSIBLE SOLUTION
Cut the power supply, close the gas
valve and call the After Sale Service.
BOILER STATUS
The boiler is in lockout position
SIGNIFICATION OF THE ERROR CODE
Fault on the DHW temperature sensor
(SS)
POSSIBLE SOLUTION
Ascertain that the SS sensor has the
right resistance values shown on the
table of the resistance values and it
harness is correct (see table on page
14)
BOILER STATUS
The boiler is in lockout position
SIGNIFICATION OF THE ERROR CODE
Fault on the CH temperat. sensor (SR)
POSSIBLE SOLUTION
Ascertain that the SR sensor has the
right resistance values shown on the
table of the resistance values and its
harness is correct (see table on page
16).
BOILER STATUS
The boiler is in lockout position
SIGNIFICATION OF THE ERROR CODE
Alteration of factory parameters
POSSIBLE SOLUTION
None. Replace the modulating PCB
BOILER STATUS
The boiler is in lockout position
SIGNIFICATION OF THE ERROR CODE
Fault on the modulation system of the
gas valve.
POSSIBLE SOLUTION
Check first the modulating coil or its
harness are not earthed or in short
circuit: if this is the case replace
them. If no result, replace the
modulating PCB.
BOILER STATUS
The boiler is in lockout position
SIGNIFICATION OF THE ERROR CODE
Main PCB (modulation) is damaged.
POSSIBLE SOLUTION
Cut and reinstate the power supply to
the boiler: if no result, replace the
main PCB.
BOILER STATUS
The boiler is in lockout position
80° 60°
65°
70° 55°
60° 50°
50° 45°
40° 40°
30° 35°
20°
80° 60°
65°
70° 55°
60° 50°
50° 45°
40° 40°
30° 35°
20°
80° 60°
65°
70° 55°
60° 50°
50° 45°
40° 40°
30° 35°
20°
80° 60°
65°
70° 55°
60° 50°
50° 45°
40° 40°
30° 35°
20°
80° 60°
65°
70° 55°
60° 50°
50° 45°
40° 40°
30° 35°
20°
80° 60°
65°
70° 55°
60° 50°
50° 45°
40° 40°
30° 35°
20°
80° 60°
65°
70° 55°
60° 50°
50° 45°
40° 40°
30° 35°
20°
80° 60°
65°
70° 55°
60° 50°
50° 45°
40° 40°
30° 35°
20°
80° 60°
65°
70° 55°
60° 50°
50° 45°
40° 40°
30° 35°
20°
80° 60°
65°
70° 55°
60° 50°
50° 45°
40° 40°
30° 35°
20°
80° 60°
65°
70° 55°
60° 50°
50° 45°
40° 40°
30° 35°
20°
80° 60°
65°
70° 55°
60° 50°
50° 45°
40° 40°
30° 35°
20°
80° 60°
65°
70° 55°
60° 50°
50° 45°
40° 40°
30° 35°
20°
SIGNIFICATION OF THE ERROR CODE
Intervention of the safety thermostat
POSSIBLE SOLUTION
Make sure the water is circulating
through the heat exchanger and the
safety thermostat TL and its harness
are not interrupted. Check as well the
CH temperature sensor (SR).
BOILER STATUS
The boiler is in lockout position
80° 60°
65°
70° 55°
60° 50°
50° 45°
40° 40°
30° 35°
20°