ATLAS D 25 K 100 UNIT
EN
4.4 Troubleshooting
Diagnostics
The boiler is equipped with an advanced self-diagnosis system. In case of a boiler fault,
the display will flash together with the fault symbol (detail 22 - 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 8 - fig. 1) for 1 second or use the RESET on
the remote timer control (optional) if installed; if the boiler does not restart it is necessary
to eliminate the fault indicated in the operation LEDs.
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.
Table. 4 - List of faults
Circulating pump diagnostics
Some faults linked to the circulating pump are signalled by the LED located around the
speed selector (fig. 38).
fig. 38
Table. 5 - Circulating pump LED indications
Fault
code
Fault
Possible cause
Cure
A01
Burner block
Pump blocked
Replace
Faulty electric motor
Replace
Faulty oil valve
Replace
No fuel in tank, or water on bottom
Refill with fuel or suck the water
Oil line feed valves closed
Open
Dirty filters (line-pump-nozzle)
Clean
Pump unprimed
Prime and find the cause of
unpriming
Ignition electrodes not properly adjusted,
or dirty
Adjust or clean them
Nozzle clogged, dirty or deformed
Replace
Unsuitable head and shutter adjustments Adjust
Faulty electrodes or earthed
Replace
Faulty ignition transformer
Replace
Faulty electrode wires or earthed
Replace
Electrode wires deformed by high tem-
perature
Replace and protect
Faulty valve or transformer electrical con-
nections
Check
Broken pump-motor joint
Replace
Pump inlet connected to return pipe
Correct the connection
Faulty photoresistance
Replace
Dirty photoresistance
Clean the photoresistance
A02
Flame present signal
with burner off
Photoresistance short circuit
Replace the photoresistance
Extraneous light strikes the photoresist-
ance
Eliminate the light source
A03
Overtemperature pro-
tection activation
Heating sensor damaged
Check the correct positioning and
operation of the heating sensor
No water circulation in the system
Check the circulating pump (See
table 5)
Air in the system
Vent the system
A04
Card parameter fault
Wrong card parameter setting
Check the card parameter and
modify it if necessary
F07
Preheater fault (the
contact does not close
in 120 seconds)
Wiring disconnected
Check the wiring
F09
Card parameter fault
Wrong card parameter setting
Check the card parameter and
modify it if necessary
F10
Delivery sensor 1 fault
Sensor damaged
Check the wiring or replace the
sensor
Wiring shorted
Wiring disconnected
F11
DHW sensor fault
Sensor damaged
Check the wiring or replace the
sensor
Wiring shorted
Wiring disconnected
F12
Card parameter fault
Wrong card parameter setting
Check the card parameter and
modify it if necessary
F14
Delivery sensor 2 fault
Sensor damaged
Check the wiring or replace the
sensor
Wiring shorted
Wiring disconnected
F16
Card parameter fault
Wrong card parameter setting
Check the card parameter and
modify it if necessary
F34
Supply voltage under
170V.
Electric mains trouble
Check the electrical system
F35
Faulty mains fre-
quency
Electric mains trouble
Check the electrical system
F37
Incorrect system water
pressure
Pressure too low
Fill the system
Sensor damaged
Check the sensor
F39
External probe fault
Probe damaged or wiring shorted
Check the wiring or replace the
sensor
Probe disconnected after activating the
sliding temperature
Reconnect the external sensor or
disable the sliding temperature
F40
Incorrect system water
pressure
Pressure too high
Check the system
Check the safety valve
Check the expansion tank
A41
Sensor positioning
Delivery sensor not inserted in boiler shell
Check the correct positioning and
operation of the heating sensor
F42
Heating sensor fault
Sensor damaged
Replace the sensor
F47
System water pressure
sensor fault
Wiring disconnected
Check the wiring
Off
Circulating pump on STANDBY
Green ON
Circulating pump Working
Green Flashing
Air venting cycle
Green/Red alternating
Circulating pump blocked due to external causes:
- Overvoltage (>270V)
- Insufficient voltage (<160V)
- Motor overload
Red Flashing
Circulating pump blocked due to internal causes:
- Motor blocked
- Damaged electronics
Fault
code
Fault
Possible cause
Cure
Min
.
4
1
7
III
II
I
cod. 3541I100 - Rev. 02 - 10/2016