Pressurisation Unit SPU 180 MAXI

Pressurisation Units

The Stuart SPU Maxi range of digital pressurisation units represent the next generation of automatic filling and pressure maintenance solutions for sealed heating and chiller systems.

Capable of filling a system from empty and then monitoring and maintaining the design fill pressure in sealed systems, Stuart SPU Maxi units are exceptionally easy to install and commission and are housed in a compact and robust enclosure suitable for either floor or wall mounting.

Units are available with one (duty), or two (duty-standby) premium quality Stuart peripheral pumps featuring all brass pump heads and continuously rated induction motors.

Utilising an unique microprocessor controller and pressure transducer, these systems feature an intuitive and easy to use menu based control system, self-diagnostic functions, configurable volt-free contact alarm connections and a Building Management System Modbus interface.

Key Features:

  • Advanced digital control system
  • Automated system fill and pressure maintenance
  • Compact design
  • Wall or floor mounted
  • Inlet and outlet configurable for left or right hand side connection with flexible hoses (supplied)
  • 3.5 and 4.5 bar pressure options
  • Single (duty) or twin pump (duty-standby) configurations
  • 10 litre tank capacity
  • High recovery water tank fill valve 12 ltrs/min @ 1 bar
  • WRAS compliant Category 5 backflow protection, type AB air gap, weir overflow and warning pipe
  • 2 year guarantee
  • Patent application submitted


Technical Specification

Product code 46725
Guarantee 2 year
System capacity Up to 300,000 litres
System fill mode  
Mounting Floor mount
Maximum cold fill pressure 8.0 bar
Maximum inlet pressure 6 bar
Number 1
Type Peripheral
Motor type Induction (thermal trip, auto reset)
Duty rating Continuous (S1)
Break tank
Capacity 18 litres
inlet valve Ball valve
Fluid category protection CAT 5 (type AB air gap with weir overflow)
Mains supply inlet ½ BSP male
System outlet 15 mm compressioon
Overflow G ¾ (19/23 mm pipe connection)
Front cover Powder coated steel
Break tank Polyethylene
IP rating IPX2
Control system
Pressure monitoring Pressure transducer (0 - 10 bar)
Ambient temperture 4 °C - 40 °C
Relative humidity 95% non-condensing
Power supply/phase/frequency 230 V a.c. / 1 / 50 Hz
Power consumption (P1) 680 Watts
Power consumption (P2) 500 Watts
Full load current 3.4 Amps
Depth 324 mm
Width 477 mm
Height 780 mm
Empty weight 34.0 Kg
Filled weight 52.0 Kg
Approvals CE

Product Variants
Part no Description
46719 SPU 130 MINI
46720 SPU 230 MINI
46721 SPU 135 MIDI
46722 SPU 235 MIDI
46723 SPU 150 MIDI
46724 SPU 250 MIDI
46725 SPU 180 MAXI
46726 SPU 280 MAXI