The TECH EU-21 CWU is a compact controller for automatic regulation of a circulation pump between the boiler and the hot water tank or buffer tank. It operates based on temperature difference and reliably protects the system from unnecessary pump operation and frost.
Highlights / Benefits
⭐ Differential temperature control – Pump runs only when there is actual heat demand
⭐ Two temperature sensors – Separate detection of boiler and tank/buffer temperature
⭐ Frost protection function integrated – Automatic activation at low temperatures
⭐ Anti-stop function – Prevents pump seizure during prolonged standstill
⭐ Manual operation possible – Ideal for maintenance and functional testing
Detailed description
Application area & target group
The TECH EU-21 CWU is designed for heating systems in which heat is transferred from the boiler to a hot water tank or buffer tank . It is suitable for single-family homes as well as smaller multi-family or commercial applications and is aimed at both professional tradesmen and operators of classic heating systems.
Everyday benefits
Thanks to the temperature-differential operating mode, the circulation pump is only switched on when sufficient heat is actually available. This prevents unnecessary cooling of the storage tank, reduces power consumption, and extends the service life of the pump.
Technology & equipment
The controller works with two temperature sensors (T1 = tank/buffer, T2 = boiler). As soon as the set temperature difference is reached and the switch-on threshold is exceeded, the controller automatically activates the pump. A fixed hysteresis ensures stable and safe operation.
Efficiency & system protection
In addition, the EU-21 CWU features an antifreeze function: If the temperature in the system drops below 6 °C, the pump is automatically switched on to prevent frost damage. The integrated anti-stop function briefly switches the pump on at regular intervals during prolonged inactivity, thus protecting it from seizure.
Compatibility & system integration
The TECH EU-21 CWU is designed for operation with 230 V circulation pumps and can be easily integrated into existing heating systems. The clear display and straightforward menu enable quick commissioning and simple parameter adjustment.
Technical data
| Feature |
Value |
| Manufacturer |
TECH Controllers |
| Model |
EU-21 CWU |
| Product type |
Pump controller / circulation pump regulator |
| Supply voltage |
230 V ±10 % / 50 Hz |
| Power consumption |
2 W |
| Operating temperature |
5–50 °C |
| Max. load pump output |
0.5 A |
| Max. load potential-free contact |
1 A |
| Temperature measurement accuracy |
±1 °C |
| Temperature range sensors |
−30 to +99 °C |
| Fuse |
1.6 A fine fuse |
| Mounting hole spacing |
86.5 mm |
Scope of delivery
Accessories / Recommendation
-
Circulation pumps for heating systems
-
Buffer tanks and hot water tanks
-
Sensor pockets and sensor mountings
-
Advanced heating controls from TECH
You will find suitable products in the corresponding categories on gemashop.de.
Assembly & Safety Instructions
Installation and commissioning may only be carried out by a qualified specialist company. Before working on the electrical installation, the device must be disconnected from the power supply. Sensors must be properly attached and insulated against external influences.
FAQ
Which systems is the EU-21 CWU suitable for?
For heating systems with boiler and hot water tank or buffer tank for pump control.
How does the controller work?
It switches the pump on and off depending on the temperature difference between the boiler and the storage tank.
Is frost protection integrated?
Yes, at low temperatures the pump is activated automatically.
Can the pump be switched on manually?
Yes, a manual mode is available.
How many sensors are used?
Two temperature sensors – one for the boiler and one for the hot water tank/buffer tank.
Is the controller preconfigured?
Yes, factory settings are available and can be adjusted.
Conclusion
The TECH EU-21 CWU is a reliable and efficient pump controller for classic heating systems with boiler and storage tank. Ideal for economical, safe, and long-lasting system operation.
