How to check your wood burner stove installation

A HETAS approved stove installation will assure you have the correct size (KW) stove for the room, the required ventilation for that stove and the correct grade chimney liner. The entire installation will be smoke tested to the chimney pot (see bottom paragraph) and required/approved carbon monoxide CO detector checked before certification is issued with a notice plate. This ensures your installation is compliant with Building Regulations 2000 Approved Document J (updated 2010) on chimneys, flues and stoves.

Very importantly, the location of your wood burner is checked for adequate fire protection to combustible materials in its proximity i.e. with floor plates and heat shields. Less of a problem when installed in a traditional brick or stone fire place, but distances to laminate or carpet flooring, soft furnishings etc. is strictly regulated.

Failure to operate any stove without a HETAS Certification will risk both life and your home insurance liability.  

You are responsible for proper maintenance of the system including regular sweeping of the chimney flue.

Building Regulations also require good access to the flue for sweeping. However, this is not always the case. Occasionally I get feedback from disgruntled DIY sweepers, who blame it on the chimney rods for not being able to push them past a 90 degree bend, in 6 inch pipe at the very back of the burner.

Generally with the more modern designed wood or multi-fuel burners today this is not usually a problem. However traditional style wood burners with a rear flue pipe outlet, make it is essential to have an access plate in the stove pipe. This is a gas tight door which can be removed to expose a round hole in the vertical stove pipe fitted to either the back or top of your wood burner.

Otherwise it is best left to a commercial chimney sweep with specialised equipment.

Wood burners with stove top flue pipe outlets will find it much simpler and cleaner to sweep via the access door, instead of removing the baffle plate and feeding chimney rods in through the door opening.

The advantage of a rear exit stove pipe is that a T piece connector to the flue pipe also has a trap at the bottom of it, to collect any soot and ash deposits that fall off the inner wall down the flue liner. Falling soot debris is common in the summer too, on windy damp days. Whereas a stove top pipe arrangement collects falling soot onto the top of the baffle plate, inside the wood burner.

Newer properties (or in a conservatory) often have flue pipes that exit directly through an external wall to a vertical rigid flue chimney pipe going to the roof line of the building. This type of installation makes for easy sweeping and emptying the soot trap, since it can all be done from outside the property.

Properties with brick chimneys, built before 1965, often have no flue lining and are in poor condition. Mortar joints are often corroded, ‘eaten’ away by acidic condensates and soot deposits. Because of this, and the risk of smoke leakage, many installers insist on lining the chimney before installing a wood burner. While it isn’t actually a Building Regulations requirement, it is the norm and certainly good practice.

The flexible (twin walled stainless steel) chimney liner is connected from your wood burner stove pipe to either the base of the chimney pot or directly to the cowl. It is highly recommend fitting a chimney cowl when you have a liner fitted. They come in many different designs, functions and prices. Your HETAS installer will advise you on which type is most suitable for your particular circumstances. A static cap cowl with bird guard is the most popular choice. It stops birds, squirrels and vermin entering the flue and greatly reduces the entry of rain water down the flue.

Smoke test pellets are a simple way of safety testing your wood burner and flue system. After you have swept the flue, to clear any soot which could block existing holes in the liner, a ‘type 2’ smoke test can be undertaken. A pack of 6x5g smoke pellets cost about £2.50 and burn for 30 to 60 seconds (choice of colours such as grey or orange – bright colours being more visible on cloudy days).

This will test several things; the operational safety of the stove (minimizing the risk of carbon monoxide in the room), whether the flue system has an adequate draught and for any leaks in the flue liner.

Firstly close all doors, window and wall air vents in the room. Preheat the wood burner for 5-10 minutes with some crumpled paper or small amount of kindling, with the door air vent open. Place one smoke pellet in the wood burner; ignite at arm’s length wearing a glove. Close the wood burner door. Check for any signs of smoke leakage: around the stove itself, stove pipe, any fittings and from under the register plate. Check if the up draught is weak or slow. Open an external window and see if the smoke velocity increases, indicating inadequate room ventilation. If your liner is fitted within a traditional brick chimney, you need to check it has not failed, so inspect any upstairs rooms with feature fire places or closed off fire places with a chimney vent. Also check the loft space for signs of smoke. Next go outside (binoculars are best) and check the smoke is only exiting through the correct pot and not any of the mortar joints in the chimney stack.