Configuration parameter
Function block [changeover valve]
31
5.7
Function block [changeover
valve]
Parameters to be set
Set or check the following parameters.
Explanation of [Hysteresis]
The temperature of the additional heat producer (e.g.
oil or gas auxiliary burner) must be higher than that of
the main heat producer (boiler or buffer) by this value
for the changeover valve to route the heat from the
auxiliary boiler, for example, to the consumers.
Explanation of [Switch priority]
This sets when the changeover valve is allowed to
switch. The following settings are possible:
•
[Temperature diff.]
The changeover valve always switches to the heat
producer with the higher temperature.
•
[Boiler pump]
The changeover valve switches back to the buffer
as soon as the boiler pump is switched on. This
used to be called "Diener" mode. This setting must
be selected when the changeover valve is installed
so that it disconnects the hydraulic connection
between the ETA boiler and the buffer.
•
[Enable burner]
The changeover valve switches to the burner as
soon as it heats up. This setting is used for burners
with low water content, because the burner may
overheat otherwise.
Explanation of [Enable criterion]
This sets when the additional heat producer (e.g.:
oil or gas auxiliary burner) may start. The following
settings are possible:
•
[Falls below required Temp.]
The additional heat producer (e.g. auxiliary boiler)
is started if the main heat producer (e.g. buffer)
cannot deliver the required temperature.
•
[Falls below set and required Temp.]
With this setting, the additional heat producer (e.g.
auxiliary boiler) starts only once the main heat
producer (e.g. buffer) cannot deliver the required
temperature and it is colder than the set
temperature [Overload at the earliest below].
Example: required temperature = 68 °C
Buffer temperature = 45 °C
[Overload at the earliest below] = 50 °C
=> the auxiliary boiler is started because the buffer
is too cold (45°C) and the buffer temperature is
also less than 50 °C.
Additional oil and gas boilers always have a lower
priority than an ETA boiler or buffer. If multiple
auxiliary boilers are installed, a priority can be set for
each auxiliary burner.
Diverter valve
Settings
Hysteresis
Switch priority
Producer 1 or Producer 2
Enable criterion
