15
Error code
Potential cause
Solution
E 5 W
Flame detected at incorrect time
There is an error in flame detection of the
burner because the flame was detected:
before ignition or
before the release of gas or
after the gas was switched off.
E 6 W
Error in the safety circuit for gas
valve
There is a heating request but gas cannot be
released.
One of the switches WOS, EOS, BOS, EPS is
open/unplugged.
E 7 W
Error of burner MCU internal
RAM
Error detected in the burner MCU’s internal
safety monitoring feature (safety variables are
no longer correct or RAM/STACK was over-
written by mistake).
E 9 W
Malfunction of water outlet tem-
perature sensor WOT
Water outlet temperature sensor WOT
has a short circuit or
is open/unplugged.
the temperature of the sensor is colder than
14 °F (-10 °C).
E 10 W
Error in the safety circuit
There is a heating request but gas is not re-
leased because a valve-actuation signal was
not activated.
E 11 W
Error of MCU watchdog gas
release
There is a heating request but the MCU watch-
dog does not release the gas path.
W 12 W
Internal error
W 13 W
Short circuit shut-off valve
Short circuit detection in the gas valve (shut-
off part) detected a current > 1000 mA and
shut off.
W 16 W
Malfunction of the MCU
Internal error of the control unit.
W 20 W
Malfunction of water inlet tem-
perature sensor WIT
Water inlet temperature sensor WIT
has a short circuit or
is open/unplugged or
the temperature of the sensor is colder than
14 °F (-10 °C).
W 21 W
Malfunction of circulation line
temperature sensor WCT
Circulation line temperature sensor WCT
has a short circuit or
is open/unplugged or
the temperature of the sensor is colder than
14 °F (-10 °C).
E 22 W
Malfunction of gas valve, modu-
lation section
Error at gas valve, modulation level, because
the modulator has a short circuit or
is open/unplugged.
W 23 W
Voltage is too high
The main power supply’s voltage detector
measured a voltage level of >16.4 V.
W 24 W
Voltage is too low
The main power supply’s voltage detector
measured a voltage level of <10 V.
E 25 W
Flue fan current consumption
error
The current detector for the flue fan has mea-
sured a current outside the permitted limits.
W 26 W
Circulation pump current con-
sumption error
The current detector at the circulation pump
has measured a current outside the permitted
limits.
