Nexus S-FS

The Nexus S-FS is a floor standing interface unit suitable for affordable homes where stored DHW and indirect apartment heating are required from a single appliance.


  • DHW cylinder capacity of 80 or 150 litres
  • Heating output up to 15kW
  • Floor standing design
  • Top connections
  • Hydraulic separation between primary and apartment heating circuit
  • Stored DHW and secondary heating
  • Insulated copper brazed AISI 316 stainless steel plate heat exchanger from SWEP
  • Insulated mains cold water (MCW) pipework and also primary pipes to plate heat exchanger
  • On/off primary control valve
  • Differential Pressure Control Valve (DPCV)
  • Mechanical temperature control of stored DHW via integral cylinder thermostat
  • Insulated painted steel case (RAL 9010) with lockable front panel
  • High efficiency ErP compliant modulating secondary heating high torque pump from Wilo
  • 4bar rated pressure relief valve on secondary heating circuit
  • Pressure gauge on secondary heating circuit
  • 12 litre expansion vessel on secondary heating circuit
  • Primary circuit strainer
  • Interface with external programmer(s) for time/temp control (volt free contact)
Performance Data S-FS 80S-FS-150
Energy efficiency classCC
Primary Flow Temperature°C8585
Primary Return Temperature°C6565
Primary Flow Ratel/min1111
Primary Pressure DropkPa2020
Integral DHW Cylinder Capacitylitres80150
Cylinder Coil Flow Temperature°C8080
Cylinder Coil Return Temperature°C6060
Cylinder Coil Flow Ratel/min1111
Cylinder Coil RatingkW1515
Cylinder Re-Heat Time (Indirect @ Δt 50°C)mins1935
Peak 10 minutes DHW deliveryl/min122192
1st hour DHW deliveryl/hour335405
Continuous DHW deliveryl/hour255255
Cylinder Re-Heat Time (Direct @ Δt 50°C)mins93174
Heating OutputkW1515
Heating Flow Temperature°C8080
Heating Return Temperature°C6060
Heating Flow Ratel/min1111
Residual Pump Head (Δp-c) @ 80/60 °CkPa4848
Residual Pump Head (Δp-v) @ 80/60 °CkPa3636