Pressurised Central Heating Systems

A sealed heating system boiler facilitates the integration of solid fuel boilers into the existing house heating system without the need for any means of incorporating a vented boiler into an unvented system and the associated pipe work and controls.


This kind of installation has been common in Europe for decades and in recent years has become virtually the only method of installing a wood burning boiler.


However, it has only recently gained poularity in the UK, and you may find it difficult to find an installer prepared to carry out this particular kind of installation.


Safety is Paramount

Traditionally solid fuel burners would be installed onto “open vented” heating systems (this means in the event of overheating, water can overflow (boil) into your header tank / feed & expansion tank).


With a sealed system safety systems are requirked to prevent and then deal with overheating:


1. Pressurised certified boilers contain a finned copper pipe within the boiler. One end of the coil is connected to the mains cold feed and the other to a suitable drain. Prior to overheating, the safety valve opens, allowing mains cold water to pass through the coil lowering the temperature very rapidly. The system requires no electricity and will therefore operate during a power cut.  This safety valve requires that you have mains cold supply to the property. Properties using water butts or wells are not suitable.


2. A pressure release valve is also included in the boiler  /  heating circuit.




In order for the boiler product to carry full warranty and support, the installation MUST be designed, installed and commissioned by a competent person with one of the following minimum technical competence sets


Set One Installer has HETAS Wet H004 and G3 Unvented certificates.


Set Two Installer has HETAS Biomass H005 certificate.


Set Three Installer has MCS Biomass certificate.


For installations onto open vented heating systems the G3 certificate is not required.


If your installation involves other heat sources (solar, gas, electric and heat pumps) then additional competences will be required.


It is the responsibility of the customer to make sure that their chosen installer meets the minimum competence requirements.


It is the installer’s responsibility to ensure that the installation is carried out in accordance with the Broseley Fires installation instructions as well as current building regulations.


Installations not complying with installation instructions will not be supported in any way.




We do not design heating systems, however we do offer guidance in the product installation instructions on the minimum requirements of the system.


The installer is responsible for any and all aspects of the installation.


A site survey will be necessary to assess the heat requirement of the property and the suitability of the desired appliance for the clients needs.


The heating system will need to be designed by the installer and detailed plans produced.


It may be necessary for other tradesman and sub-contractors to become involved in the installation (such as electricians).  #


These individuals should be working to the installers plans and specifications.


The installer is ultimately responsible for the final installation (hence they will need to approve all sub-contracted work).


Finally the installer MUST provide a commissioning certificate to the client for the final completed installation.