Multi-fuel Burner Usage and Care
After installation you will be provided with important guidelines to follow for the first use of your stove. Please do take note of these and follow them carefully, they are there to protect you and your new appliance.
The First Four Fires: Always use half a load of fuel for the first four or five fires in your new fireplace. The paint, putties and seals on the fireplace and flue needs to cure and the fireplace needs to settle. Please do not touch any painted parts during these small fires – the paint is still curing and may smudge or peel off later.
Each appliance is different and you will need to familiarise yourself with the workings of your stove so please take time to read the manual.
Remember to keep safety distances of combustibles (curtains, rugs, wood, electronics) from the sides, back and top of the wood stove.
Fuel Selection - good dry wood & quality anthracite
Multi-fuel burners can burn either wood or anthracite. With either fuel it is imporant that it is dry and of good quality.
Always burn DRY fuel. This means wood that has been seasoned for at least one year and has a 20% or less moisture content. Unseasoned (wet) wood contains a great deal of moisture, which reduces the burning temperature of the fire and causes additional smoke and pollutants. Wet or poor quality anthracite is highly corrosive due to impurties in the fuel. Excessive moisture in your fuel will result in oxidation (rusting) of metal components in the structure of your fireplace and potential damage to insulation and vermiculite.
Additionally, wet fuel (especially wood) will make the glass of your wood stove black. When the flue on your closed combustion fireplace is not hot enough, especially when you burn unseasoned/wet wood—a dark, sticky substance known as creosote forms onto the walls of the flue. Creosote is flammable which accumulates over time in the flue pipes. This can choke the wood stove but also can lead to chimney flue fires if the creosote catches alight.
Hardwoods are preferable to softwoods, because softwoods tend to contain more resins, which create smoky odours and deposits in your flue system. Softwoods are also less dense with a lower calorific value per volume.
Check that the wood you are buying is dry and well-seasoned by striking two pieces together. Dry wood gives a resonant ‘clack’, while unseasoned wood make a dull ‘clunk’ like sound. Using a moisture meter to test the moisture content of wood is the most accurate way. Moisture meters can be obtained from us.
South African produces some of the best anthracite in the world but most of the premium grade is exported to Europe. It is imporant to buy the best quality anthracite you can find as poor quality anthracite has impurities which when burned are not only bad for the environment, the health of your family and the integrity of your closed combustion stove and flue system. Even stainless steel gets corroded with the high heat and corrosive impurities.
Start stacking, splitting and storing your wood now for next season. Stack your wood loosely off the ground in a criss-cross fashion to allow the air to circulate freely. If possible, store it under a roof to keep it dry. It is better to keep wood at least eight months to a year before use so that it is properly seasoned. Start to search for and stock-pile high quality anthracite. Summer prices are lower than those in Winter so a good time to buy.
Never burn treated wood, in some instances (copper chrome-arsenate treatment) it can release poisonous fumes. Wood collected from the seashore is not suitable because it contains corrosive salts. Don’t burn garbage, painted timber or particle board —these all release pollutants
How to set an upside down fire.
To get your wood stove to light quickly and effectively, use the upside down fire. To do this:
- Stack 3 large logs side by side in your wood stove to make a base. Try to get them together as tight as possible. The objective is not to leave a space for the live coals to fall through to the bottom layer. The tighter the bottom logs are placed together the longer and more effective your fire will burn.
- Stack a further 3 medium to large pieces of wood (split) perpendicular to the logs and on top of the logs.
- Place some fire lighters down (if you use these) and then your kindling.
- Light your fire. The layers will start to burn from the top down, creating live coals which will start to pile up on the next level, causing it to ignite. The secret to this method is to create a domino effect of ignition from one layer to the next
Why do it this way?
The kindling burns first and begins to create a pressure differential. This creates a draw in the flue pipe. The wood stove also starts to warm up and so the whole system starts to “fire”. As the draw happens, the fire starts to burn and continues to heat up creating more draw. The smaller wood burns first and then the larger and largest logs. When you are ready, just add more wood. As the firebox starts to warm up, the bottom logs heat up and start to release volatiles. The heat and flames in the layers above, ignites and cleanly burns these volatiles.
In the traditional packing method, the first gases (volatiles) driven out of the wood, travel unburned through the flue pipe forming flammable creosote build-up onto the internal flue walls and releasing unburned carbon dioxide into the environment.
The upside down fire makes a dramatic difference in conventional fireplaces producing a long clean burn and will usually also solve any start-up smoking problems.
How much fuel to use
Never exceed the recommended maximum load. Doing so may result in damage to the fireplace which will shorten its usable life span or may even damage it beyond repair.
It is relatively easy to work out how much wood should be burnt in a specific kilowatt close combustion fireplace.
Wood has a potential calorific value of about 5kW. Use this and subtract the moisture content of the wood being burnt to get the calorific potential of your wood.
e.g. 5kW – 20% = 4.8kW
If you have a wood stove that is rated as 10kW then to calculate the maximum kilogram per hour consumption rate by dividing this by your wood value.
e.g. 10kW ÷ 4.8kW = 2.08 kg of wood per hour.
With different grades and sizes of anthracite available this calcualtion becomes difficult. It is best to only use small amounts of anthracite if you do use it. We advise to add it to a good bed of coals made from wood and to do this at night before going to bed.
Step 1: Calculate potential
5kW – moisture content % = wood potential output
Step 2: Calculate wood per hour
10kW (stove max output) ÷ wood potential output
How to control your multi-fuel burner
Fire’s food is oxygen, so regulate this and you can control your closed combustion fireplace. More oxygen means more heat output as the combustion processes is accelerated and vice versa.
Closed combustion stoves have a combustion chamber and will have a primary air intake control. Some stoves have a secondary and even tertiary controls which may or may not be adjustable.
Usually the primary control is at the bottom of the stove and secondary at the top. The secondary air intake supplies oxygen to the top part of the combustion chamber for secondary combustion of gasses/volatiles. The secondary air intake also acts as air wash system to keep the glass of the unit clean.
Please refer to your manual for specific instructions.
All oxygen controls fully open. It may also be necessary to leave the door/glass a crack open until the wood has properly caught fire (Few minutes).
Please be aware that leaving the door/glass open for extended periods of time will overheat and damage the fireplace.
Depending the required heat output the air controls can be opened up or closed down accordingly.
More oxygen – bigger flames, higher kW output, higher temperatures and higher fuel consumption.
Less oxygen – smaller flames, lower kW output, lower temperatures and lower fuel consumption.
Before new wood is added to the combustion chamber – open all oxygen controls fully. Do this by slowly open the door/glass of the unit to prevent smoke from entering the room.
Leave all oxygen controls open until the newly loaded wood is well lit, before the oxygen controls are set lower.
Night time operation
Load the maximum allowed load of wood. Open all air vents and ensure the wood is well lit. Completely close or choke down the primary and if possible, secondary, air intakes.
A slow rolling flame in the top part of the combustion chamber is the optimal result.
Fireplace Servicing and maintenance
Regular inspection and cleaning of your appliance is very imporant. Remember this is fire and so considered operation and care is required to stay safe. During season inspections should be done daily.
Some key points and tips
- If using a glass cleaner ensure you only spray the cleaner onto a cloth or onto some paper towel and wipe down like that. NEVER spray the glass. The cleaner may get onto the fire rope and then this gets damaged.
- If the glass is very black then check the wood. It is likely wet or unseasoned. You can buy a wood moisture meter if you want to check.
- With black glass, you need to clean this before burning again otherwise you risk cooking the black grime onto your glass. Cleaning can be done with a piece of newspaper or kitchen towel that is damp. Dip this into the very fine ash that you get after your fireplace has burnt (make sure not to burn yourself if the ash is still hot). Using the ash on the glass rub the black off.
- Then wipe the glass down with a damp cloth or more kitchen towel.
- Take care when disposing of the ashes. These can take a long time to cool down.
- Ensure you regularly check the fire rope, seals and pipes for damage. Most important is the fire rope on the doors. This needs to seal properly.
- Just like a car, certain parts of your fireplace may need to be replaced over time (fire rope, vermiculite boards most commonly).
TOP TIP: Remember to schedule an annual service to check your fireplace, flue system and to give it all a good clean.
Suggested Daily Maintenance
- Remove all the ash from the fireplace
- Clean the glass of the unit (see above)
- Check fire rope on the door and if applicable the ash drawer.
- Check panels, bricks and vermicullite for cracks or damage.
- Vacuum out the interior of the stove if you have an ash VAC.
- Use a soft brush to clean the ceramic plates.
- Brush off any rust if visible then use fireplace polish only on cast iron and steel.
After season it is highly recommended for the unit to be decommissioned, after it has been thoroughly cleaned and serviced. Decommissioning involves treating the cast iron and metal parts of the unit with a suitable anti rust application, like grate polish. In some instances it may be necessary to block the flue pipe to prevent moistures air to travel down the flue to the unit. If the flue must then be unblocked before re-use.