GST131, Wilo pump GST141, Wilo pump
GST131, Wilo pump GST141, Wilo pump

Return temperature unit


The ESBE series GST100 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 GST100 is delivered with a 3-way thermostatic mixing valve, which comes in two versions: fixed temperature or adjustable temperature setting.
  • Thermostatic constant temperature control
  • Available with fixed or adjustable temperature setting
  • High class insulation shell
  • High efficiency circulation pump

Product range

GST1x1 front-01
GST131, GST141
GST1x1 side-01
Series GST130, Fixed temperature setting range °CConnection IConnection JWeight kgNoteNTCNTC = National Trade Code
61120100GST13125Wilo 25/650/55/60°CG 1"G 1½"5.0The Return Temperature Units Series GST130 are delivered with three wax elements: 50/55/60ºC. Factory assembly: 55ºC. 
Series GST140, Adjustable temperature setting range °CConnection IConnection JWeight kgNoteNTCNTC = National Trade Code
61120200GST14125Wilo 25/650-75°CG 1"G 1½"5.4  

Installation support

Installation examples
Return Temp unit_Appl1-01
Installation instruction GST100
Installation instruction Wax element GST131
Installation instruction GST100, Wilo Pump

Technical data

Technical data
Pressure class: PN 6 
Media temperature, max.: +100 °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: <0,20 
The integrated Thermostatic mixing valve Max. differential pressure drop: 100 kPa
Rangeability Kv max/Kv min, A-AB: 100 
Leakrate in % of flow*, A-AB Tight 
Leakrate in % of flow*, B-AB max. 3% of Kvs 
* Differential pressure 100kPa (1 bar) 
Opening temperature - Fixed temperature: 50, 55, 60 °C
Opening temperature - Adjustable temperature: 50-75 °C
The integrated Circulation pump Power supply: 230±10% VAC, 50/60Hz 
Power consumption - Wilo 25/6: 3-45 W
Enclosure rating: IP X4D 
Insulation class: F 
EEI - Wilo 25/6: <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
Circulation pump Wiring LTC100_A-01
The circulation pump should be preceded by a multi-pole contact breaker in the fixed installation.
Dimensioning $name
Dimensioning guide - Please see data sheet

Accessories and spare parts

Spare parts trade codeNoteData sheetInstructions manual


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 


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


Thermostat VTC931 55°C
57000200VTC931Thermostat, 55°C    


Thermostat VTC931 60°C
57000300VTC931Thermostat, 60°C Load valve VTC317  

Download area

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Data sheet GST100
Installation instruction GST100
Installation instruction Wax element GST131, GST132
Installation instruction GST100, Wilo Pump
2D Image GST131, GST141
3D drawing (stp file) GST131, DN25
3D drawing (stp file) GST141, DN25