Pump controller ST-21 Tech controllers
Goal
The ST-21 controller with an LED display is designed to control a central heating water circulation pump. The controller's task is to turn on the pump when the temperature reaches the set value and turn it off if the boiler cools below the set value by the set hysteresis value. This operating mode prevents unnecessary pump operation, which saves electricity, extends the pump's service life and increases its reliability. The ST-21 controller can also act as a thermostat, turning off the pump after the set temperature is reached. The controller also has an ANTI-STOP function that prevents the circulation pump from jamming in the off-season (the pump turns on approximately every 10 days for 1 minute). Additional protection is the anti-freeze function that prevents water from freezing in the installation. When the temperature drops below 5 °C, the pump will turn on permanently.
Functions performed by the controller
- central heating or hot water pump control
- ability to act as a thermostat
- anti-stall function
- anti-freeze function
Controller equipment
- central heating temperature sensor
- LED display
| Parameter | Unit of measurement | value |
| Power source | V | 230V +/-10% /50Hz |
| Maximum power consumption of the controller | W | 2 |
| Ambient temperature | °C | 5÷50 |
| Maximum pump output load | A | 1 |
| Temperature setting range CO | °C | 25÷85 |
| Hysteresis | °C | 1÷10 |
| Measurement accuracy | °C | 1 |
| Sensor temperature resistance | °C | from -30 to 99 |
| Fuse insert | A | 1,6 |
| Sensor cable length | m | 1,5 |
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