Operating & Maintaining Your Stove
Many solid fuel-fired appliances are expected to work 24 hours a day, 365 days a year, keeping us warm and supplied with constant hot water. However, like any other machine, they work better and last longer when correctly installed, burn the right fuel and are properly maintained. This leaflet will guide you through the basics of owning and running a stove, from a general overview, through lighting your stove, burn efficiency, the fuel to use, to maintenance and safety.
Fire Door /Window
Doors should be tight fitting and may have mechanisms to allow adjustment to achieve a good fit. Many doors will have heat-proof rope seals to aid a gas tight seal. This seal is subject to wear and tear and will need to be replaced when its effectiveness is reduced. Using a stove with its doors open will reduce efficiency, and with some designs may result in overfiring and damage to the appliance. Excess air intake will cool the fire and draw cold air into the house.
Primary air enters the appliance below the grate and the control is often in the ash pit door. This controls the burning rate of the fire. Please see your appliance’s instruction manual for correct operation.
Soot can fall down the flue and collect on the throat plate. This needs clearing to reduce the risk of these deposits igniting and to ensure there is a clear flue way for smoke to leave the appliance.
Secondary air enters from above the grate and provides oxygen for the secondary combustion of gases and vapours given off during the primary combustion. This helps combustion efficiency so that smoke emission is minimised.
The flue outlet is generally situated on either the top or the rear of the stove. Combustion gases leave the stove through this outlet to be carried to the chimney through a connecting pipe. The gasses eventually safely leave the dwelling at the top of the chimney. Building Regulations require that all products of combustion are discharged safely to the outside atmosphere.
Many solid fuel appliances have fire bricks lining the floor and walls. Their purpose is to help insulate the fire bed, improving the stove’s efficiency by retaining heat. Broken fire bricks should be replaced immediately.
Most stoves incorporate a pan to collect ashes as they are produced from burning fuel and fall through the grate, allowing regular easy removal.
The main controls on a stove are for regulating the flow of air reaching the fuel, which in turn will affect the heat output and the efficiency of burning. Instruction manuals usually show how to operate the controls to achieve the best combustion and efficiency. You may find a flue pipe temperature gauge helpful to set the controls for your appliance.
Chimneys should be swept at least twice a year when burning wood or bituminous house coal and at least once a year when burning smokeless fuels. The best times to have your chimney swept are just before the start of the heating season and after any prolonged period of shut-down. If sweeping twice a year, the second time should be after the peak of the main heating season.
In the first instance always refer to your stove instruction manual. The following can be used as general guidance. An efficient burn of fuel providing heat to the room requires three things:
Time – the burning should have time to happen within the appliance before the combustion air pu_shes the flame up the chimney – where the heat released will be wasted.
Temperature – solid fuel burns efficiently at a high temperature giving rise to negligible smoke. If the temperature is insufficient then much of the potential heating value of your fuel will be lost and increased smoke will be discharged from the flue.
Turbulence – arrange the fuel in a way which ensures the air and combustion gases mix for an efficient burn, taking care to not overfill the appliance.
The flame picture in a healthy fire will be somewhere between:
Vigorous flame just reaching the exit of the appliance (noticeable when getting the appliance up to temperature but shouldn’t be maintained)
Lazy flame that moves across the whole space within the stove (very efficient when up to temperature)
Red-hot embers – very efficient, but may need more fuel before the embers die down.
Things to Know When Buying Logs
Dry wood (well seasoned) burns better than wet wood (green logs). Wet wood is much less efficient, and if you can get them to light at all, logs that are not dry provide a fire that smoulders and creates lots of tars and smoke. These tars can be corrosive, potentially damaging the lining of the flue and increasing the danger of a chimney fire. Wet logs will tend to blacken glass in stoves even if the stove is designed to keep the glass clean. When trying to burn wet wood, the fire has to boil off the water before any heat is provided to the room. Well seasoned logs can have twice the heating value of green logs.
Only burn dry wood, either by buying it dry or by seasoning green logs. Dry in a sunny, well-aired space for one or two summers, keeping the rain off in the winter. Radial cracks and bark that comes off easily suggest well-seasoned wood; better still, check with a moisture meter. First, calibrate the meter and then measure a freshly split surface to get the best reading.
When buying logs, the seller should advise whether they are from hardwood or softwood tree species (or mixed) and if they meet the European standard EN ISO 17225-5 for graded firewood. The general difference is that hardwoods tend to be denser than softwoods. This means that a tonne of hardwood logs would occupy a smaller space than a tonne of softwood logs.
Denser wood tends to burn for a longer period of time meaning fewer ‘top ups’ are required to keep a log stove burning for a given length of time. Since the heating value is approximately proportional to the weight of the wood (for the same moisture content), hardwood logs are typically priced as more expensive than softwoods when bought by volume.
Ensure that your firewood is not contaminated, e.g. with paint or preservatives. Treated wood should never be used in a stove because it can produce harmful gas emissions which may affect your health. Burning contaminated wood is also more likely to corrode flue linings and damage the chimney as well.