Baxi 500 Assure System 2

The Baxi Assure 500 System 2 boiler is the perfect solution for homes with more than one bathroom or a high demand for hot water and is compatible with the Baxi cylinders and the Megaflo Eco cylinder.

The boiler is compact and small enough to fit in a kitchen cupboard and has a heated condensate trap to help avoid frozen condensate pipes in the winter.

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Features and benefits    |    Dimensions    |    Product literature    |   Technical specifications   |   Related products   |    FAQs

Features and benefits


  • A: Boiler width = 395mm
  • B: Boiler height = 700mm
  • C: Boiler depth = 285mm
  • D: Side clearance = 2.5mm
  • E: Upper clearance = 178mm
  • F: Lower clearance = 150mm
  • G: Front clearance = 5mm in operation (450mm for servicing)
Baxi  500 System 2 Line Diagram_ALT
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Product literature

Technical specifications

  • 15, 18 and 24kW Combi (Natural Gas or LPG)
  • Natural gas to LPG conversions
  • Lightweight and compact cupboard fit
  • Pre-heated Siphonic Condensate Trap
  • Positive fit PrV connection pipe
  • Combined PrV with separate drain
  • Certified OpenTherm
  • 2 years parts and labour warranties


  • View full technical specifications
Technical Specifications   Baxi 515 Assure System Baxi 518 Assure System Baxi 524 Assure System
Sales Code   7814318 7814319 7814320
Natural gas or LPG   Yes Yes Yes
Inlet supply pressure (natural gas) mbar (nominal) 20 20 20
Maximum Gas Rate (G20) Omax m³ / hr 1.64 1.97 2.61
Heat Input CH kW (max) Gross (OnHs)  15.5 18.6 24.7
  kW (min) Gross (OnHs) 4.9 4.9 4.9
Heat Output CH (non-condensing) kW (Max) (Pn) 15 18 24
  kW (Min) (Pn) 4.8 4.8 4.8
Heat Output CH (condensing) kW (Max) (Pnc) 16.3 19.9 26.3
  kW (Min) (Pnc) 5.2 5.2 5.2
Heat Input domestic hot water (DHW) kW max gross (OnwHs)  N/A N/A N/A
Heat Output domestic hot water (DHW) kW max  24  30  30
Water heating efficiency class   A A
Permanent live required   Yes  Yes  Yes 
External fuse rating (on connection board) Amps F0.5A L250VP F0.5A L250VP F0.5A L250VP
Pump overrun   Yes Yes Yes
Integral 'boiler only' frost thermostat   Yes Yes Yes
Maximum DHW flow rate (Delta T @35'C rise)  l/min - - -
Minimum DHW flow rate required   l/min 
Minimum operating DHW pressure required bar 0.5  0.5  0.5 
Integral expansion vessel Size (litres) 
Maximum capacity of the CH system Litres  100  100  100 
Integral automatic bypass   Yes  Yes  Yes 
Installer Lift Weight (kg) 28.5  28.5 28.5
Height  mm 700 700 700
Width mm 395 395 395
Depth mm 285 285 285
Side (mm) mm 2.5 2.5 2.5
Upper (mm)  mm  178 178 178
Lower (mm)  mm  150 150 150
Front  mm  5 5 5
Front (Service) mm 1000 1000 1000

More information


  • How to recharge the air gap on a Megaflo unvented cylinder
  • How to reset a Baxi boiler
  • How do I bleed a radiator?

If you've noticed that water is dripping from the safety pipe outside or through the tundish on the outside of your cylinder, this is an indication that the air gap in your cylinder needs recharging. Watch our video to find out how you can easily fix this yourself, without calling a heating engineer.

Read full FAQ

Read how to reset your boiler, whether it has a dedicated reset button, an ON/OFF/SELECTOR switch or a thermostat control knob.

Read full FAQ

If you have cold spots at the top of your radiators, it means that there is trapped air that needs to be removed so your radiators will heat your room efficiently. Follow our simple steps for bleeding your radiators.

Read full FAQ