Since the late 1980’s it has been convenient for Architects, builders and construction companies to install gas boilers in newly built apartments in the London and Essex areas away from outside walls. Usually using a twin flue type system hidden within the concealed ceiling and wall void space area of the property. This was fine as far as saving on space, after all no one really wants to see a boiler and the associated pipe work on display, however it was impossible to inspect the integrity of the flue system. So although you may have had your boiler serviced on a regular basis, the gas engineer could not inspect the flue system as it was hidden.
Eventually it was proved that this type of flue system was dangerous and it could be linked to causing the death of someone. Legislation and the gas regulations were then changed, so that any gas engineer who came across these types of gas boilers classified them as being ‘at risk’.
Owners and landlords of these properties are now required to install both inspection hatches as well as carbon monoxide detectors. You may need several inspection hatches depending on how long and where the flue terminates, other points to note is whether your flue system enters communal areas of the building or other peoples properties. The size of the inspection hatch should be a minimum of 300mm x 300mm so that the gas engineer can clearly inspect the flue system.
With many of the boilers that were installed using these type of flue systems coming to the end of their lifespan, such as the Powermax 140, 155, 185, the Maxol micro turbo, Keston boilers and Geminox boilers, it may make more economic sense to change to an electric heating system boiler as when you eventually do need to replace the gas boiler if you want to replace it with another gas boiler then you will also need to replace the entire flue system, in effect having to take down the entire ceiling or find a place to relocate the boiler. You will also probably have seek permission from the building management to relocate the flue terminal.