No heat pump operation when outside air temperature less
than
Prerequisite: Heat pump as standby boiler
The heat pump stops working below the set temperature.
This avoids operation with high energy consumption when
the temperature outside is cold.
Maximum outfeed temperature for heat pump operation
Prerequisite: Heat pump as standby boiler
If a flow temperature higher than the set value is required,
the main boiler takes over.
Main boiler minimum runtime
Prerequisite: Heat pump as standby boiler
If the main boiler is in operation, it only shuts down after
the minimum runtime of the main boiler if the criteria for
heat pump operation are fulfilled. This should prevent
excessively short runtimes of the main boiler.
Minimum temperature of secondary boiler
When the secondary boiler reaches the specified
temperature, the loading pump is started and switches the
isolating valve.
Temperature difference between secondary boiler and
buffer tank
Temperature difference between secondary boiler and
upper temperature in layered tank to activate the loading
pump of the secondary boiler.
Oil valve shut delay
If the current boiler temperature of the secondary boiler
falls below the value that is set under
“Minimum
temperature of secondary boiler”
, the isolating
valve only switches once the set duration has elapsed.
4.6.3 Boiler 2 - Service
System menu
Boiler 2
Control secondary boiler variably to the target value
▪ NO: The secondary boiler is operated with the boiler
temperature that is set on the secondary boiler
thermostat.
▪ YES: The boiler temperature of the secondary boiler is
regulated to the target temperature specified from the
heating circuit or DHW tank.
Sensor input of backup boiler sensor
Sensor input to which the sensor for the secondary boiler
is connected.
Pump output of secondary boiler unloading
Pump outlet to which the loading pump of the secondary
boiler or the secondary boiler switch valve is connected.
Control of boiler 2 pump
Definition of control signal for pump type used.
⇨ See "Activation options of pump outlets" [page 124]
Maximum speed of boiler 2 pump
If you need to limit the maximum speed of the loading
pump of the secondary boiler for systemic reasons, you
can do so by adjusting this parameter.
Invert secondary boiler isolating valve
YES: If the valve switches incorrectly, the way it is
controlled can be adjusted using this parameter.
Burner relay
▪ A: Standby boiler is controlled according to the program
that is set.
▪ 1: Standby boiler was started manually.
▪ 0: Standby boiler was stopped manually.
4
Parameters overview
Boiler 2
70
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