ST-21 controller for hot utility water pump

Controller for domestic hot water pump

RELEVANT INFORMATION

The ST-21 domestic hot water controller is a universal controller equipped with two temperature sensors and is designed to control a circulating pump. The task of the controller is to switch the pump on when the temperature difference between the sensors exceeds a specified value (T2-T1 ≥ Δ), if T2 ≥ minimum threshold for switching the pump on.

The pump is switched off when T2 ≤ T1 or T2 < minimum pump switching threshold - 2°C (fixed hysteresis) or when T1 reaches the preset temperature. Where: T2 - the temperature of the boiler T1 - the temperature of the boiler (buffer). This prevents unnecessary operation of the pump and unwanted cooling of the tank when the flow temperature drops, which saves electricity and extends the life of the pump.

This increases its reliability and reduces operating costs. The ST-21 DHW controller is equipped with a system that prevents the pump from stagnating during a prolonged shutdown. Every approximately 10 days, the pump is switched on for 1 minute.

An additional function is to protect the installation against freezing. When the temperature at the boiler or tank sensor falls below 6°C, the pump is permanently switched on. It is switched off when the circulation temperature reaches 7°C.

The manufacturer provides a 2-year guarantee for the dedicated product, subject to its terms and conditions. We encourage you to visit the downloads tab, where the following documents are available: manual with technical documentation, declaration of conformity, terms of guarantee.

FFUNCTIONS PERFORMED BY THE CONTROLLER

• Control of the DHW pump.
• Anti-stop function
• Anti-freeze function
• Control of non-voltage output

CONTROLLER EQUIPMENT

• LED display
• Two temperature sensors
  
  

CHARACTERISTICS

• Supply voltage: 230V ±10% /50Hz
• Max. power consumption: 2W
• Operating temperature: 5°C-50°C
• Max. load of the pump output: 0.5A
• Max. load of voltage free contact output: 1A
• Measurement accuracy: 1°C
• Temperature resistance of KTY sensor: -30÷99°C
• Fuse link: 1.6A