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[External heat source] function block
Configuration parameter
5.8
[External heat source] function
block
Parameters to be set
Set or check the following parameters.
Explanation of [Switch off boiler at]
This parameter determines at what temperature of the
external heat source the ETA boiler switches to
[Locked] mode.
If the temperature of the external heat source lies
below this temperature [Switch off boiler at], the ETA
boiler always supplies the heat. If this temperature is
exceeded, the ETA boiler switches to [Locked] mode.
Explanation of [Enable diverter valve]
Optional: Only with diverter valve
This parameter is used to set the minimum
temperature for the switchover between the ETA boiler
and the external heat source.
If the temperature of the external heat source is below
this minimum temperature, the diverter valve switches
to the ETA boiler, which then supplies the heat. If this
temperature is exceeded, the valve switches to the
external heat source, which supplies the heat.
Explanation of [Pump safety run]
This boiler temperature from external heat producers
is used to forcibly switch on all consumers in order to
discharge heat.
Explanation of [Enable temperature]
Optional: only with charging pump
This parameter sets the minimum temperature of the
external heat source, for starting the charging pump of
the external heat source.
Explanation of [Thermostat diff.]
Optional: only with charging pump
This parameter is used to set the minimum difference
between the temperature of the external heat source
[Ext. heat] and the tank that needs charging [Tank tem-
perature], to start the charging pump of the external
heat source.
Explanation of [Hysteresis]
Optional: only with charging pump
To start the charging pump, the external heat
temperature must be higher than [Enable tempera-
ture]. At the same time, the [Thermostat diff.] plus the
[Hysteresis] must be exceeded with respect to the tank
temperature.
Example:
[Enable temperature] = 50 °C
[Thermostat diff.] = 5 °C
[Hysteresis] = 2 °C
=> the charging pump is only switched on when the
external heat has exceeded the minimum temperature
of 50 °C and is also 7 °C warmer than the tank that
needs charging.
The charging pump is switched back off as soon as the
external heat is cooler than the tank temperature plus
the [Thermostat diff.], or if the external heat falls below
the [Enable temperature].
Explanation of [MixValve runtime]
This parameter sets the running time for the mixing
valve actuator, the time needed to turn it from the
closed to the fully open position.
Set the running time according to the information
on the mixing valve actuator's type plate.
Ext. heat
Switch off boiler at
Enable diverter valve
Pump safety run
Charging pump
Enable temperature
Thermostat diff.
Hysteresis
Return
MixValve runtime
