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7 Controller functions
7.1 General controller functions
7.1.1 Temperature difference
The controller compares the temperatures of the various measuring points and op-
timally charges the storage tank. If the collector temperature exceeds the storage
tank temperature, the solar circuit pump is switched on. Monitoring and protection
functions ensure safe operation.
7.1.2 Thermostat
- Cooling
If the measured temperature exceeds the target value, output A1 is switched on
until the measured temperature falls below the target value - hysteresis (e.g. 60°C
- 10K).
- Heating
:
If the measured temperature falls below the target value, output A1 is switched on
until the measured temperature reaches the target value + hysteresis (e.g. 60°C +
10K).
7.1.3 RPM control
The output A1 can be operated using an RPM control.
Minimum - 30 %
7.2 Protective functions
The controller is equipped with the following protective functions.
7.2.1 Anti-freeze protection
This function must be activated if the water or glycol mixture can freeze. If the tem-
perature of the collector sensor drops below 5°C, the solar circuit pump is activated
and heats the solar circuit using the heat exchanger in the storage tank.
7.2.3 System protection
If the collector temperature exceeds 130°C, the solar circuit pump is switched off to
protect the system components.
If the collector temperature drops below 120°C, the solar circuit pump is switched
on. This function is always activated.
7.2.3 Pump blocking protection
If the solar power system is out of commission for an extended period of time due
to poor weather, for example, the solar circuit pump may “seize”. To prevent this, the
controller switches the pump on for 30 seconds after 10 days.
