Pressure, the key to a good system design

Pressurisation, the key

Our experience, research and targeted investigations have taught us that most issues within H&V systems are closely related to insufficient pressurisation. Often even straightforward problems are overlooked during design, installation and maintenance.

As a result, the system fluid’s quality is seriously compromised, and a potentially fatal series of events will occur. This dramatically reduces the efficiency of the system and also causes premature failure of major system components. Often it ends up in high operating costs for the plant and considerable expense for the owner and annoying inconveniences for the end-user. Parts need to be replaced, and the system must be cleaned persistently, and time and again, chemicals are applied. All this to achieve a “status quo” for the circulating fluid.

Breaking the cycle of work and costs starts with the pressurisation system

Break the cycle of work and costs

A poorly designed, installed and maintained pressurisation system can lead to negative pressures around the circuit. Air can be drawn in through Automatic Air Vents, gaskets and micro leaks. High pressure situations can lead to water being emitted through the safety valves and the subsequent frequent addition of further raw refill water. The introduction of fresh oxygen-rich water depletes any level of corrosion inhibitors that may be present.

The onset of corrosion is then inevitable, and the cycle continues:

  • Air continually gets into the system.
  • Corrosion starts to occur.
  • Dirt & sludge begin to build-up.
  • The system is cleaned and treated.
Air in the system

Corrosion inhibitors do not affect the content of inert gases such as nitrogen and carbon dioxide that are present in large volumes and reduce the operating efficiency of the system.

SpiroExpand - Pressurisation

A full range of solutions

Each heating or cooling system puts different demands on a pressure control system. Also, operators place additional requirements on the equipment of the pressure control systems, on the possible signal exchange with other parts of the installation or control system and operational reliability.

SpiroExpand covers a full range of solutions, from the most basic setup to the most complicated system. If you can’t find the right plan for you, we’ll be happy to create a customised set up specifically for your problem.

SpiroPress TopControl - Expansion Vessel


The TopControl Modular is a modular expansion and pressure controller for use in combination with external low pressure EG expansion Vessels (safety valve 0.5 bar). In contrast to MultiControl systems, the TopControl series employs electronic speed-controlled pressure control pumps and electronic pressure relief valves. The even higher operational pressure range of 23.5 bar allows for the use of these units in an enormous range of different types of equipment.

Membrane expansion vessels

These are ‘passive’ pressure management systems. A preset gas pressure in the membrane expansion vessel is used for pressure control. Because membrane expansion vessels do not have a make-up function, we ideally combine this type of pressure control with a vacuum degasser including a make-up function.

More information on our SpiroExpand product range

SpiroExpand covers a full range of solutions, from the most basic setup to the most extended, complicated system. All units are used to provide full vacuum degassing of the system water. Make-up water is degassed prior to system entry, offering substantial long-term protection.

Get more info on our full assortment of SpiroExpand products

SpiroExpand Configuration Software

Customise your pressurisation set-up to maximise the performance of your heating or cooling system. Whether you are designing, dimensioning or planning as part of an initial consultation, this tool will help you, just enter the key basic parameters and you’ll be presented with various solutions in a matter of minutes. The preferred solution can be either downloaded or sent via email.

Start the SpiroExpand selection tool