GRA311, Wilo Pump
GRA311, Wilo Pump

Circulation unit


The ESBE series GRA300 is a circulation mixing unit which is intended for heating circulations where the outstanding flow and temperature control are required. Equipped with two shut-off valves with thermometers, check valve, high class insulation shell and high efficiency circulation pump. This compact unit is equipped with 3-way rotary progressive mixing valve and actuator. 

The Circulation Mixing Unit ensures best regulation performances independent from flow rate and low oversizing risk thanks to progressive valve characteristic, as well as the working possibility with most controllers available on the market.

  • Outstanding flow control thanks to the progressive characteristic of the valve
  • Ready to use with most controllers available on the market
  • High class insulation shell
  • Compact design
  • "Quick fit" connection between Valve and Actuator

Product range

GRA300 front_A-01
GRA300 side_A-01
Series GRA311 IConnection JWeight kgNoteNTCNTC = National Trade Code
61043100GRA31120Wilo 15/7,5G ¾"G 1"4.5  

Installation support

Installation examples
Installation instruction GRA300

Technical data

Technical data
Pressure class: PN 6 
Media temperature, max.: +110 °C
min.: 0 °C
Ambient temperature, max.: +50 °C
min.: 0 °C
Working pressure: 0.6 MPa
Connections: Internal thread (G): ISO 228/1 
External thread (G): ISO 228/1 
Insulation: EPP λ 0.036 W/mK 
Media, Heating water  (in accordance with VDI2035) 
Water/Glycol mixtures, max. 50 %
(above 20% admixture, the pump data must be checked)  
Water/Ethanol mixtures, max. 28 %
Material, in contact with water: Components of Brass, Cast iron, Steel 
Sealings material of: PTFE, Aramid fibre, EPDM 
EEI (Energy Efficiency Index), Wilo circulation pump: <0,21 
The integrated Mixing valve: Max. differential pressure drop: 100 kPa
Close off pressure: 200 kPa
Leakrate in % of flow*: <0,05 %
* Differential pressure 100kPa (1 bar) 
Characteristics: See diagram 
The integrated Actuator: Actuator type: ARA661 Quick fit 
Control signal: 3-point 
Power supply: 230 ± 10% V AC, 50Hz 
Power consumption: 5 VA
Running time 90°: 120 s
Enclosure rating: IP41 
Protection class: II 
The integrated Circulation pump: Type: Wilo RSTG 15/7,5 
Power supply: 230±10% VAC, 50/60Hz 
Cable length: 3 m
Power consumption: 4-75 W
Enclosure rating: IP X4D 
Insulation class: F 
EEI (Energy Efficiency Index): <0,21 
Characteristics: See diagram 
Conformity CE_A-01
LVD 2014/35/EU
EMC 2014/30/EU
RoHS 2011/65/EU
Valve characteristics VRG430_RGB_GB_C-01
Circulation pump Wiring LTC100_A-01
The circulation pump should be preceded by a multi-pole contact breaker in the fixed installation.
GxA300_elkoppling PWM-01
Pumpspeed could be controlled by PWM signal
Constant speed GRA300 Constant dimensioning_A_en-01
Dimensioning, Pump Capacity diagram
Example: Start with the heating demand of heating circuit (e.g. 25 kW) and move horizontally to the right in the diagram to the Δt = 15°C (temperature difference between flow and return of the heating circuit). Next go up and find working point and read the available pressure of the pump on the left – ∆p = 62 kPa.
Variable pressure GRA300 Variable dimensioning_A_en-01

Accessories and spare parts

Options trade codeNoteData sheetInstructions manual


Manifold for 2 circulation units, without integrated hydraulic separator function.
66000500GMA321Manifold GMA321, DN20 Manifold for 2 units.


Manifold for 3 circulation units, without integrated hydraulic separator function.
66000600GMA331Manifold GMA331, DN20 Manifold for 3 units.
Spare parts trade codeNoteData sheetInstructions manual


ESBE GSP931 Pump RSTG 15/7,5 Wilo
67003100GSP931Pump RSTG 15/7,5 Wilo    


ESBE GSP903 Thermometer upgrade set, 2 pcs/package
67000600GSP903Thermometer upgrade set, 2 pcs/package    


ESBE GSP932 PWM cable Wilo RSTG, 3m
67003900GSP932PWM cable Wilo RSTG, 3m    


ESBE GSP933 Ball valves incl thermometer DN20 G¾", 2 pcs/package
67003300GSP933Ball valves incl thermometer DN20 G¾", 2 pcs/package DN20, G¾"  


ESBE GSP930 Insulation circulation unit DN 20
67003000GSP930Insulation circulation unit DN 20    


ESBE GSP933 Ball valve DN 20
67003500GSP933Ball valve DN 20 DN20  


ESBE GSP933 Ball valves incl thermometer DN20 G1", 2 pcs/package
67003800GSP933Ball valves incl thermometer DN20 G1", 2 pcs/package DN20, G1"  


ESBE GSP961 Actuator ARA661 120s 230V 3p QF
67006100GSP961Actuator ARA661 120s 230V 3p QF    


ESBE GSP912 Adaptor kit VRG&ARA.
67000700GSP912ESBE valves series VRG and Actuators series ARA DN20-DN32  

Download area

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Data sheet GRA300
Installation instruction GRA300
2D Image GRA311
3D drawing (stp file) GRA311, DN20

Related products



Series GMA300 is manifolds for 2 or 3 circulation units including insulation according to EnEV2014 and wall brackets.

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