GST131, Wilo pump GST132, Grundfos pump GST141, Wilo pump GST142, Grundfos pump
GST131, Wilo pump GST132, Grundfos pump GST141, Wilo pump GST142, Grundfos pump

Return temperature unit

GST100

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
GST1x2 front-01
GST132, GST142
GST1x2 side-01
Series GST130, Fixed temperature setting
Art.no.ReferenceDNPumpTemperature 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. 
61120400GST13225Grundfos 25-5050/55/60°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
Art.no.ReferenceDNPumpTemperature range °CConnection IConnection JWeight kgNoteNTCNTC = National Trade Code
61120200GST14125Wilo 25/650-75°CG 1"G 1½"5.4  
61120300GST14132Wilo 25/7.550-75°CG 1¼"G 1½"6.1  
61120500GST14225Grundfos 25-5050-75°CG 1"G 1½"5.5  
61120600GST14232Grundfos 25-7050-75°CG 1¼"G 1½"6.2  

Installation support

Installation examples
Return Temp unit_Appl1-01
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Installation instruction GST100
Installation instruction Wax element GST131, GST132
Installation instruction GST100, Wilo Pump
Installation instruction GST100, Grundfos 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 
Conformity: PED 2014/68/EU, article 4.3 
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
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 
Characteristics: See diagram 
Conformity CE_A-01
LVD 2014/35/EU
EMC 2014/30/EU
RoHS 2011/65/EU
ErP2015_A-01
ErP 2009/125/EC
ErP 2015
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EnEV 2014
Circulation pump Wiring LTC100_A-01
The circulation pump should be preceded by a multi-pole contact breaker in the fixed installation.
GST130: Available pressure, Wilo pump GST130 Wilo_dimensioning_GB_verA-01
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.
GST130: Available pressure, Grundfos pump GST130 Grundfos_dimensioning_GB_verA-01
GST140: Available pressure, Wilo pump GST140 Wilo_dimensioning_GB_verA-01
GST140: Available pressure, Grundfos pump GST140 Wilo_dimensioning_GB_verA-01

Accessories and spare parts

Spare parts
ImageArt.no.ReferenceDesignationNational trade codeNoteData sheetInstructions manual

GSP902

ESBE GSP902 Thermometer 2pcs
67000200GSP902Thermometer 2pcs   

GSP901

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

GSP901

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

GSP901

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

GSP901

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

VTC931

Thermostat VTC931 55°C
57000200VTC931Thermostat, 55°C    

VTC931

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
Installation instruction GST100, Grundfos Pump
2D Image GST131, GST141
2D Image GST132, GST142
3D drawing (stp file) GST131, DN25
3D drawing (stp file) GST132, DN25
3D drawing (stp file) GST141, DN25
3D drawing (stp file) GST141, DN32
3D drawing (stp file) GST142, DN25
3D drawing (stp file) GST142, DN32