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6.3.2 Faults
The faults are displayed by flickering display of QAA 88 device. Current fault number is displayed in P 15
parameter. In case more faults occur simultaneously first of all the fault with higher number will be displayed.
The non-reversible fault 4 must be quitted after its elimination which is done on the introductory display of
QAA device (i.e. leave P 15 parameter of the device up to the introductory display) by the simultaneous
pressing of keys (+arrow up,- arrow down) for the period of approx. 3 sec. Display flickering will disappear.
The reversible faults disappear automatically after their elimination.
In case of fault 10 - of heating branch sensor (only in case of mixing heating circuit) the three-way mixing
valve closes. As the temporary variant (before we replace the sensor) we can select the boiler operation at
the fixed temperature (P 24 parameter) plus the heating branch three-way mixing valve switch-over to MAN
position. We select setting of heating branch three-way mixing valve manually. After the fault elimination we
again select the automatic boiler operation and we switch over the three-way mixing valve back to AUTO
position. Until the heating branch sensor is replaced the fault is signalled on QAA 88 device.
In case of fault 1 i.e. exceeding of max. boiler temperature the boiler might be shut down through the safety
thermostat set to approx. 100 °C. This fault is non-reversible and it is necessary to de-block the safety
thermostat after the boiler has cooled down. The de-blocking button is found under the black plastic cover.
Tab. no. 9 Faults
Image
Sensor
Fault description
Boiler response
1
B2
Exceeding of safety temperature (max.
boiler value)
Boiler shut-down. The pumps are still
working. The three-way valve opens and
water is withdrawn into the heating
system.
2
B5
Exceeding of fuel feeder temperature
Fuel feed according to the set algorithm
so that the burning fuel is returned into
the burner.
3
Motor
heating
protection
Exceeding of fuel feeder motor winding
temperature
Boiler shut-down. The primary pump is
still working. After the winding has cooled
down and the heating protection has re-
switched put the boiler into operation.
4
B2
Extinction
of
boiler.
The
outlet
temperature in a given time interval does
not grow. The absence of fuel, feeder
blockage etc. might be the reasons.
Boiler shut-down. The protection against
fuel fire penetration is active
7
B3
Overheating of warm water in HW
reservoir
End of HW heating. Three-way valve
turns to HC.
8
B1
HC overheating
HC heating and HC pump shut-down.
9
-
Time validity.
If absence of voltage on regulator is
longer than approx. 3 days counting of
time (date, time) will stop. It is necessary
to set current time a date.
Boiler heats to the set temperature in the
first period on Monday.
