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Setback mode
If there is no demand for heating or hot water, the boiler is in setback mode. This mode is indicated by the green
LED flashing on the boiler display. In this mode, the minimal boiler temperature is maintained only by the min. fan
power without the pump operation (factory setting 65 °C). If the minimum boiler temperature is reached, the fan and
the feeder are switched on only in a defined time delay for a specific period of time to prevent the extinction of the
boiler. By definition, the fan is running longer compared to the feeder to reach the complete burning of fuel.
The boiler should not be disconnected from the power supply. In case of the boiler disconnection from the
power supply, the time on the control unit may stop and thus switching of the time mode may be incorrect.
In this case, a capacitor, which is part of the control unit, is used to maintain the correct date and time
settings. The correct date and time will be maintained max. 8 hrs.
In extreme cases, the fuel can burn through into the tank. In case the boiler is switched off (but not
disconnected from the power supply), the protection against the fuel burning through into the tank is
active. In case of an extended power supply outage, it is recommended to remove fuel from the burner to
prevent its burning through into the tank.
6.1.2
Safety thermostat
The safety thermostat is located on the left side part of the base shell and is used for the boiler operation shut-down
when the temperature exceeds the safety temperature. The safety thermostat must be set to 100 °C, i.e. to a higher
temperature than the set maximum boiler temperature(90 °C). Releasing the safety thermostat is indicated on the
display of the boiler. The fuel feeder and the fun are stopped. Unblocking the safety thermostat must be done
manually - after the cover dismantling and the trap pressing.
In case of the safety thermostat repeated switching off, the boiler must be shut down and the cause of the boiler
repeated overheating must be determined. After releasing the safety thermostat, the primary pump (or pumps) is
still running.
6.1.3
Temperature sensor on the fuel feeder
If on the temperature sensor there is the temperature set in the parameter limit burning through, fuel feeding will be
accelerated in order to move the burning fuel to the burner. When the temperature drops below the set value minus
hysteresis, the boiler will return to the original mode. This safety function works only if the boiler is supplied with
electricity.
Sensor pocket of the fuel feeder is placed at the bottom of the fuel feeder.
6.1.4
Flue gas sensor
Based on the flue gas temperature, extinction of the boiler in the automatic and the setback mode is monitored.
6.1.5
Emergency fire-extinguishing equipment
In case of the fuel burning through into the feeder (temperature at the feeder reaches 95 °C), BVTS valve
(TS 130, STS 20) opens the water supply to the hopper and the burning fuel is extinguished, and after a drop in
temperature at the sensor by 6
°
C the water supply is stopped.
6.1.6
Forced withdrawal of excess heat
6.1.6.1 Forced withdrawal of the boiler excess heat
If the boiler temperature exceeds the factory setting (88 °C), the so called forces withdrawal of the excessive heat
into the heating circuit occurs - if it is enabled. The fan and the feeder are not active. After the current desired boiler
temperature falls down, the boiler will return to the automatic mode. In case the boiler temperature has reached 100
°C and the safety thermostat was blocked – the safety thermostat must be unblocked manually.
6.1.6.2 Forced withdrawal of excess heat to the water heater
Forced withdrawal of excess heat to the water heater is defined by the set value of the forced withdrawal of the heat
to HW.
