What is a Flue Damper?

However, anything that restricts the flow of dangerous flue gas exiting the stove, could potentially be a bad thing and therefore all factory-made dampers should still leave enough space in the flue pipe to maintain a reasonable updraught. In theory then it will be impossible to completely close it off. Under normal operating circumstances a damper should never be required and for safety reasons, in the UK and Ireland, flue dampers must only ever be fitted when an updraught problem has been identified.

Whilst a good updraught is a fundamental requirement for the safe operation of your stove, a flue draught which is too strong however can limit the control you have over the burn rate of fuel and your fuel economy so that you will need to reload your stove more often. A lot of the excess heat generated will quickly go straight up the chimney as well. In addition you will not be able to turn down the stove when it is getting too hot or when you want to put the stove in 'slumber' mode. 

In many photographs of European stoves, particularly Scandinavian and German, you will often see flue dampers where a connecting flue pipe is also shown. In these countries a flue damper is fitted within the flue system as standard – but it is important to point out, that there are strict laws in these countries governing the regular cleaning and maintenance of flues so that an annual safety certificate can be produced for insurance companies. Without this regular cleaning a damper could very quickly become clogged, especially if wet wood is burned, and this could quickly restrict the flow of flue gases further to the point where the operation of the stove becomes unsafe. Remember, where there is very poor updraught then a stove has the potential to leak dangerous carbon monoxide into the room.

At The Stove Yard we would NOT recommend fitting a flue damper without first consulting a Hetas Registered Installer or other approved competent person. They will be able to carry out the appropriate tests, including a flue draught pressure test, in order to identify if there are any other issues that may be causing the lack of control or excessive fuel usage. In our experience these can also include a badly made stove (even from a good stove maker), a badly fitting stove door (people have been known to lean on them each time they get up from lighting the stove) and probably the most common fault, a worn out door rope seal.