Expansion Vessels

When a boiler is heated, water in a heating system expands as a result of thermal pressure. Expansion vessels – also known as expansion tanks – are used to manage the increased volume and pressure of the heated water.

Diaphragm expansion vessels offer a simple and intelligent solution that will maintain the correct pressure for the perfect functioning of a heating system. They operate without an electrical current, compressor or pump, instead a diaphragm separates the vessel into a water and gas chamber preventing the gas from diffusing into the water.

reflex logo

Reflex Expansion Tanks

The Reflex range of diaphragm expansion vessels can be used for a wide range of pressure ranges and nominal volumes, flat or cylindrical in shape depending on the installation site, and with fixed, half diaphragm or exchangeable bladder (full diaphragm).

Tubman Heating has a range of Reflex expansion tanks available, from 8 litres – 500 litres capacity.

Contact our Sales Team today to discuss your options.

Product Name


Reflex NG N Series Expansion Tank


NG & N Series

  • From 8 litres – 1 000 litres
  • Welded diaphragm expansion vessel
  • For sealed heating and cooling water systems
  • 70⁰C – 120⁰C operating temperature
  • Maximum operating pressure 6 bar
  • 1.5 bar inlet pressure
reflex G series expansion tanks


G Series

  • 100 – 500 litres
  • Replaceable bladder
  • For closed heating and cooling systems
  • With feet
  • 70⁰C – 120⁰C operating temperature
  • Maximum operating pressure available 6 bar, 10 bar and 16 bar
  • 3.5 bar upstream pressure
reflex s series expansion tank


S Series

  • 2 – 33 litres wall mounted with a non-replaceable bladder
  • 50 – 600 litres with feet and non-replaceable diaphragm
  • Specifically designed for solar systems, but also used in heating and cooling systems
  • 70⁰C – 120⁰C operating temperature
  • Maximum operating pressure available 10 bar
  • 5 – 3 bar inlet pressure
reflex DC series expansion tank


DC Series

  • 50 – 600 litres
  • Non replaceable half-diaphragm
  • Suitable for use in water systems with heightened corrosion protection requirements
  • No flow-through, no shut-off and no drain
  • Maximum operating pressure available 10 bar