Pressure units come in all shapes and sizes. The principles are all similar and can be designed to contain the net or gross expansion of a heating system. Units can be "off-the-shelf" items or designed specifically for the application. All are designed with high and low pressure alarm circuits for boiler interlocking and are commissioned by ourselves for site parameters

A filler unit is designed to top-up a heating system in the event of water loss, from a leak or radiator being replaced etc. The gross expansion of the system is stored in an expansion vessel, which is normally sited next to or close to the unit.

A compact unit is used on smaller heating systems where the expansion vessel is an integral part of the filler system, offering both aesthetic and cost conscious qualities.


Servicing is probably the most important part of any pressure unit or booster unit. Without servicing the pressure units effectiveness could be detrimental to the heating system. Our engineers are amongst the highest trained in the country and can set systems parameters for small low, medium and high temperature hot water heating systems.

You can download pdfs of our Sealed System Units, Boosters and Fill & Spill units by clicking the appropriate link below.

Sealed System

  • F Series
  • MM1Series
  • WMF Series2
  • WMF Series
  • Boosters

  • B Series
  • B Series B
  • BG Series
  • HM Series
  • TKS Series
  • email us

    Fill & Spill Units

  • C1 Series
  • C2 Series
  • D Series
  • N Series 1
  • N Series
  • A typical ‘filler’

    A compact unit