Two circles secondary electronic heating system

Two circles secondary electronic heating system
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Heating system for radiator and floor heating - Electronic

mixing valve

Content of package:

  • Heating pump unit with electronic (servomotor) mixing valve (2 pieces)
  • Euroster UNI2 controller
  • 2-way insulated distributor 3/4"

Pump unit with electronic mixing valve



Heating circuit supplier pump unit


  • Space-saving, compact design
  • Insulated, aesthetic
  • Quick and easy assembling
  • Mechanic friend therefore is more economical to build up
  • Plannable mechanic costs
  • Adjustable heating water temperature per heating circuit
  • Reasonable price/value rate
  • Long lifetime for the best quality components



Pump unit with servomotor mixing valve 3/4”

DN20 pump units can be connected to heating systems with powers up to 33kW, with a very
low energy consumption assured by high efficiency synchronous circulating pumps.


EPP insulation box (Measurements: 180x302x142 mm).
Centre distance 90 mm.
Especially suitable to manage medium-low powers in small rooms,
thanks to its centre distance of only 90 mm.
For power up to 33 kW (with Δt 15 K).
Maximum flow 1900 l/h.
Kvs value: 5.5
For an accurate measuring or for higher flows, please refer to the curves shown in the next page.


The unit for 1/2” (130 mm) circulating pumps consists of:

  • Connection.
  • 3-way mixing valve with adjustable by-pass. Through the bypass
    (adjustable from the front part) it is possible to mix on the
    supply line a quantity of water coming back from the return
    line of the system, from 0 up to 50%.
  • High efficiency synchronous pre-wired circulating pump (for the models that include it).
  • Flanged ball valve supplied with in-handle thermometer (coded red, range 0°C-120°C).


  • VFlanged ball valve with non return valve 20 mbar (which can be excluded by rotating the handle by 45°)
    supplied with in-handle thermometer (coded blue; 0°C-120°C).
  • “T” Connection for mixing valve.
  • Connection.



Approximate data  for applications in low and medium temperature heating systems


Approximate power and flow of the installation

Recommended circulating pump

Residual lifting power

Approximate surface of the underfloor heating system

8 K

12 kW - 1300 l/h

Wilo Yonos Para RS 15/6

4,5 mH20

Up to 100 m²

8 K

17 kW - 1900 l/h

Wilo Yonos Para RS 15/7,5

5 mH20

Up to 170 m²

15 K

23 kW - 1300 l/h

Wilo Yonos Para RS 15/6

4,5 mH20


15 K

33 kW - 1900 l/h

Wilo Yonos Para RS 15/7,5

5 mH20



Working principle


During the regular working process, with the mixer completely closed on the recy cling for example, a part of the fluid is aspirated from the pump all along the by-pass line. This quantity of fluid (narrow blue arrow) represents 50% of the capacity of the mixer (red arrow). As a result, one has a very high delivery capacity and a reduced temperature.









Servomotor TRM20:


3 points servomotor for mixing valve, bidirectional,
Operating range of 90°, 230V, 105 s., torque 2 Nm. IP40.










UNI2 controller

UNI2 controller

UNI2 is a universal controller designed for heating systems equipped with:

  • Two central heating circuits with mixing valves (e.g. for heater supply and floor heating)
  • Domestic hot water (DHW) circuit
  • DHW circulation circuit

Thanks to its grapichal display the Euroster UNI2 cooling-heating controller gives precise and wide ranged information about its continous operation, making it lot easier to set and to check the device. The unit also includes anti-freeze function which prevents malfunctions outcoming of the freezing.
Furthermore the controller is useable for buffer tank and boilers, since it has an overheating protection. During overheating it overrides the signal from the room thermostatic.


Euroster UNI2 cooling-heating controller is equipped with: multifunctional double mixing valve controller,
quick to assemble set, graphical LCD display, advanced microprocessor technology, knowledge of five commander units in one and the thermal sensors.
Controller functions: mixed circles cooling-heating, two thermostat signal receptions, start two mixing valves, start domestic hot water pump, optional operating modes, start circulating pump, outer-temperature sensor, weekly programming option, launch other boiler based on room thermostat, anti-stop function, freeze prevention, overheating prevention.


UNI2 controller

The heating system controller is equipped with two separate mixing valve and pump controllers, which can be launched by room thermostat signal and tuned by outer temperature signal. Able to receive two separate thermostat signals which are voltage free. The mixing valves can be controlled to heat and cool by a weekly program.
Euroster UNI2 cooling-heating controller provides two other functions: launch domestic hot water pump of which’s operational mode is selectable (primary or secondary) even by weekly programming. Furthermore its able to launch a circulating pump which has great advantages that its launchable in two different operational modes: temperature surveillance or time definition. Both of these even by weekly programming.
+ automatic fail-safe pump control
+ floor temperation
The heating system controller is able to launch other boilers (ex.: gas boiler).

Opening dinamics:

UNI2 open dinamics

UNI2 example system:

UNI2 working

1. External temperature sensor
2. Room control unit for circuit 1
3. Temperature sensor for circuit 1
4. Central heating pump for circuit 1
5. Mixer for circuit 1
6. Supply temperature sensor
7. Room control unit for circuit 2
8. Temperature sensor for circuit 2
9. Central heating pump for circuit 2.
10. Mixer for circuit 2
11. Feed pump for DHW tank
12. Temperature sensor for DHW tank
13. DHW circulation pump
14. Temperature sensor for DHW
15. Circulation

UNI2 controller wiring:

UNI2 wiring

Back of the UNI2 controller:

UNI2 controller back

UNI2 sizes:

UNI2 sizes

Length of sensors included int he set:
1. Outdoor temperature sensor (5m)
2. Powertemperature sensor (1,5m)
3. CH1 circuit temperature sensor (1,5m)
4. CH2 circuit temperature sensor (1,5m)
5. CH3 circuit temperature sensor (1,5m)
6. Additional heat source temperature sensor (1,5m)

UNI2 technical data






2-way insulated distributor 3/4"


Maximum flow rate up to 2m3/h, 50kW (Δt20K)
max. 6bar.
Connection for pump units: ¾”
Connection for buffer tank: 1”
Insulation box section size: 100x100x360mm