GSA111, Wilo pump GSA112, Grundfos pump
GSA111, Wilo pump GSA112, Grundfos pump

Return temperature unit


The ESBE series GSA100 is a return temperature unit designed for applications, where a return temperature control is required. Equipped with two shut-off valves with thermometers, check valve, high class insulation shell and high efficiency circulation pump. The GSA100 is delivered with a 3-way rotary mixing valve and actuator. The Return Temperature Unit GSA100 ensures pre balanced system and best regulation performances, as well as the working possibility with most controllers available on the market.
  • System pre balance
  • Best regulation performance
  • High class insulation shell
  • Ready to use with most return temperature and boiler controllers

Product range

GSA1x1 front_A-01
GSA1x1 side_A-01
GSA1x2 front_A-01
GSA1x2 side_A-01
Series GSA100 range °CConnection IConnection JWeight kgNoteNTCNTC = National Trade Code
61140100GSA11125Wilo 25/6by external control unitG 1"G 1½"5.6  
61140300GSA11132Wilo 25/7.5by external control unitG 1¼"G 1½"6.4  
61140500GSA11225Grundfos 25-50by external control unitG 1"G 1½"5.7  
61140700GSA11232Grundfos 25-70by external control unitG 1¼"G 1½"6.5  

Installation support

Installation examples
Return Temp unit_Appl1-01
Installation instruction GSA100
Installation instruction GSA100, Wilo Pump
Installation instruction GSA100, Grundfos Pump

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, Iron, Copper 
Sealings material of: PTFE, Aramid fibre, EPDM 
EEI (Energy Efficiency Index), Wilo circulation pump: <0,21 
Grundfos circulation pump: <0,20 
The integrated Mixing valve Max. differential pressure drop: 100 kPa
Close off pressure: 200 kPa
Rangeability Kv/Kv min, A-AB: > 100 
Leakrate in % of flow*: <0.05 %
* Differential pressure 100kPa (1 bar) 
Characteristics: See diagram 
The integrated Actuator Control signal: 3-point 
Power supply: 230 ± 10% VAC, 50Hz 
Power consumption: 5 VA
Running time 90°: 60 s
Enclosure rating: IP41 
Protection class: II 
The integrated Circulation pump Power supply: 230±10% VAC, 50/60Hz 
Power consumption - Wilo 25/6: 3-45 W
Power consumption - Wilo 25/7.5: 3-76 W
Power consumption - Grundfos 25-50: 2-34 W
Power consumption - Grundfos 25-70: 2-53 W
Enclosure rating: IP X4D 
Insulation class: F 
EEI - Wilo 25/6: <0,20 
EEI - Wilo 25/7,5: <0,21 
EEI - Grundfos: <0,20 
Characteristics: See diagram 
Conformity CE_A-01
LVD 2014/35/EU
EMC 2014/30/EU
RoHS 2011/65/EU
PED 2014/68/EU, article 4.3
ErP 2009/125/EC
ErP 2015
EnEV 2014
Valve characteristics VRG330_GB_A-01
Wiring, Actuator ARA600 3point_A-01
The actuator should be preceded by a multi-pole contact breaker in the fixed installation.
Circulation pump Wiring LTC100_A-01
The circulation pump should be preceded by a multi-pole contact breaker in the fixed installation.
Available pressure, Wilo pump $name
Dimensioning, Pump Capacity diagram
Example: Start with the heat output of the boiler (e.g. 40 kW) and move horizontally to the right in the diagram to the chosen Δt (recommended by boiler supplier), which is the temperature difference between the riser from the boiler and the return to the boiler (e.g. 85°C - 65°C = 20°C).

Move vertically up to the curves representing load unit performance. Check that the pump curve overcomes the additional pressure drops in system components such as pipes, boiler and storage tank.
Available pressure, Grundfos pump $name

Accessories and spare parts

Spare parts trade codeNoteData sheetInstructions manual


ESBE GSP902 Thermometer 2pcs
67000200GSP902Thermometer 2pcs   


ESBE GSP901 Pump RKA 25/6 Wilo
67000100GSP901Pump RKA 25/6 Wilo DN25 


ESBE GSP901 Pump RKA 25/7.5 Wilo
67000300GSP901Pump RKA 25/7.5 Wilo DN32 


ESBE GSP901 Pump UPM3 25-50 Grundfos
67000400GSP901Pump UPM3 25-50 Grundfos DN25 


ESBE GSP901 Pump UPM3 25-70 Grundfos
67000500GSP901Pump UPM3 25-70 Grundfos DN32 

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Data sheet GSA100
Installation instruction GSA100
Installation instruction GSA100, Wilo Pump
Installation instruction GSA100, Grundfos Pump
2D Image GSA111
2D Image GSA112
3D drawing (stp file) GSA111, DN25
3D drawing (stp file) GSA111, DN32
3D drawing (stp file) GSA112, DN25
3D drawing (stp file) GSA112, DN32