Multi fuel stoves provide an enclosed environment in which a number of different types of fuel can be burnt to heat your home.
Multi fuel stoves work in a similar way to wood burning stoves and open fireplaces, where fuel is burnt to provide heat to a room. Multi fuel stoves are designed to increase the heat output from burning solid fuel in your home by creating a controlled environment where the most amount of heat can be produced per piece of fuel.
This guide is for how to use multi fuel stoves. Multi fuel stoves are slightly different to wood burning stoves, and you can read the complete list of differences here.
As multi fuel stoves create a controlled environment in which to burn fuel to create heat, there can be a multiple vents that are used to control the airflow into the stove. These vents help dictate how fast the fire is burning through the fuel, and therefore how much heat is being produced.
Air vents on multi fuel stove also influence systems within the stove such as air wash (which helps to keep the glass clear) and secondary combustion (which helps produce more heat through burning off waste gases).
There are a number of different things that need to come together to have a successful fire in multi fuel stove, and so this guide explains how to use a multi fuel stove to provide heat to your home.
This complete guide goes into detail on the following areas of using a multi fuel stove:
- Building and lighting a fire.
- Using the air vents to control the fire.
- Keeping a multi fuel stove burning.
- Getting the most heat from a multi fuel stove.
- Keeping the glass clean.
I’ve used our own multi fuel stove as an example throughout the guide to help explain how to use a multi fuel stove.
How To Build A Fire In A Multi Fuel Stove
Multi fuel stoves can burn a number of different types of fuel such as wood and coal. We typically only burn wood and so I’ll be explaining how to build a wood fire in a multi fuel stove, but make reference on how to use coal in a multi fuel stove.
Before building any fire in a multi fuel stove, the ash pan should be checked to see how much ash has built up from previous fires.
Depending on how long you expect your next fire to burn, you may want to remove the ashes from the pan as excess ash can prevent air getting to the fire from below. Ash will fall through the grate at the base of the firebox during the fire and collect within the ash tray.
We generally clean out the ashes from our multi fuel stove between every fire just to be sure.
We also don’t worry too much about any excess ash left in the firebox, as it helps to insulate a wood fire. Any ash at the bed of a firebox should be removed before having a coal fire to prevent any blockages, because coal requires a source of air from below to burn efficiently.
Building a wood fire in a multi fuel stove should be started by taking single sheets of crunched up newspaper and placing them in the stove. The newspaper shouldn’t be over crumpled or likewise squashed into the stove, otherwise air won’t be able to get in between the sheets.
Firelighters can also be in between the newspaper if required.
Several small bits of dry kindling (softwood is preferred) should then be added on top of the newspaper in a crisscross arrangement so that air can also get in between the bits of wood.
Once a wood fire is built in your multi fuel stove it should look something like the below:
How To Light A Fire In A Multi Fuel Stove
With the fire built, the multi fuel stove can be prepared before being lit.
Lighting a fire in a multi fuel stove can typically be the most difficult part of the whole process, because various elements need to come together for the fire to successfully take hold of the fuel without going out.
A lack of oxygen is a common cause for many fires to go out after lighting, and so it’s important to ensure that all of the controllable air vents on a multi fuel stove are fully open before lighting the fire.
There are two controllable vents on our particular model of multi fuel stove, which are located on the front and underneath.
The primary vent, which serves air into the stove from below the fire, is located on the front of our stove near the bottom. The vent is a sliding cylinder that we rotate to open and close. This vent should be fully open before starting a fire.
The secondary vent, which supplies air to the stove from above the fire, is located underneath our multi fuel stove, with the handle to control the vent sticking out the front. Simply pushing and pulling this vent closes and opens this vent respectively, and this vent should also be fully open prior to lighting the fire.
At this point, the fire is almost ready to be lit. Another common cause of a fire going out after lighting is a lack of draft on the stove from the flue.
Cold air can become trapped within the flue and prevent warm air from escaping the multi fuel stove. As a result, fresh air is prevented from entering the stove causing the flames to subside, and the fire to go out.
By opening the door to the stove to build the fire, the stove and the flue should have been warming up to room temperature. You can also ‘prime the flue’ by taking a lit rolled up piece of newspaper (or any other form of heat) and placing it under the opening of the flue within the stove.
This process helps to further warm the flue and get the draft on the stove going, significantly helping a fire get going once lit. If you can see the smoke rising up into the flue, then this should be sufficient for lighting a fire.
To start the fire, the newspaper at the bed of the firebox should be lit at various points across the stove, to help the flames spread to the kindling and to get the fire going quickly.
Once the fire has been lit, depending on how well a fire gets going in your multi fuel stove, you can leave the stove slightly open, or fully close it. We always close the door to our stove after lighting, and in our case having the vents fully open provides enough oxygen to the fire to get it going.
If you’re having trouble getting the fire going in your multi fuel stove with the door to the stove closed, you can leave it cracked open for a few minutes while the fire takes hold of the fuel.
However, the door on a stove shouldn’t remain open for the duration of the fire because the airflow into the stove can’t be controlled. If the door is left open, and the air vents become useless and the fire can’t be controlled. (I’ve discussed leaving the door open on a stove in another article here.)
The fire should then be left to get going by itself, or topped up with smaller bits of fuel as required until a bed of hot coals has been provided. Once a bed of hot coals has been reached, larger logs can be used on the fire without smothering it.
How To Control A Multi Fuel Stove
Once the fire has visibly taken hold of the fuel, the air vents on the multi fuel stove should typically be closed down so that the fire doesn’t burn through the fuel too quickly.
When burning wood, close down the primary vent on the stove until its partially open or completely closed. Wood burns best with a source of air from above and so the secondary vent is used to control the fire.
When burning coal, the secondary vent should be mostly closed down, but not completely closed or air may not be provided for the secondary burn or air wash systems. The primary vent is then used to control the fire.
If the fire struggles to continue when closing down the vents, leave them open until later into the fire once the temperature within stove has risen. The vents can then be closed down bit by bit until you’re happy that the fire is receiving enough air to not got out.
The aim of a multi fuel stove is to produce the most amount of heat for every piece of fuel consumed. In order for this to happen, the airflow into the stove must be controlled.
If too much air is provided to the fire, the stove will burn hotter but will burn through the fuel at a much faster rate. If too little air is supplied, the fire will be starved of oxygen and won’t burn the fuel efficiently.
Hotter therefore doesn’t always necessarily mean better when it comes to using multi fuel stoves, and this can be seen on the thermometer that came with our stove.
The picture shows that there is a temperature range in which the stove is best performing (creating the most amount of heat per piece of fuel).
If the stove is operating at a less than optimum temperature then the fire is more likely to produce creosote, which can lead to blackening of the glass and require the flue to be cleaned more often.
If the stove is running too hot, the fire is burning through the fuel inefficiently and you’ll find yourself needing to add fuel to the fire more often in return for diminishing gains in heat output.
Depending on the size of your multi fuel stove, there should be one or two larger sized logs on the fire at any one time. The amount of fuel inside the stove shouldn’t exceed its design capacity, as overloading the stove can cause it to over fire and potentially cause damage to the stove over time.
The air vents should be controlled in conjunction with how much fuel is on the fire to keep your multi fuel stove burning within its ‘best operation’ temperature range.
We try to keep the temperature of our stove just below 470°F (240°C) so that’s it’s operating within the optimum temperature range, while still producing great amounts of heat and only needing another log on the fire every so often.
If the multi fuel stove is running too hot, partially close down the secondary vent if burning wood, and the primary vent is burning coal, until the temperature of the stove reaches optimum performance.
If the stove isn’t burning hot enough, add more fuel to the fire (without overloading it) and/or increase how far the air vents are open to increase the oxygen supply to the fire.
How To Keep A Multi Fuel Stove Burning
To keep a fire in a multi fuel stove burning during its initial stages, you should build and light a fire in your stove as I’ve described earlier within this article.
Once a fire in a multi fuel stove has reached a point where there is a good bed of hot coals, simply keeping the stove topped up with fuel and using the air vents to adjust the oxygen supply as required will help keep a multi fuel stove burning for long periods of time.
Keeping the temperature of the stove within its ‘best operation’ temperature range will ensure that each piece of fuel is being burnt the most efficiently, while still producing great amounts of heat and keeping it burning for the longest time possible.
Another important aspect of keeping a fire burning inside a multi fuel stove is using hardwood logs instead of softwood, and ensuring that the logs are dry enough to efficiently burn in the fire.
Hardwood is typically denser than softwood and so takes longer to burn through and produces more heat overall as a result. If you’re looking to keep a multi fuel stove burning for longer periods of time between loads, look to use hardwood logs such as Oak and Ash.
You should ensure that any wood you’re using is dry and low in moisture content. It’s recommend that wood used in a multi fuel stove has moisture content of 20% or less. Kiln dried or seasoned wood is typically viable for use on a stove fire, but you can use a moisture meter to read the exact moisture content of wood before using it to ensure that it’s dry enough.
Wet wood is harder to catch alight and harder to burn, and can eventually put the fire in your multi fuel stove out.
How To Get The Most Heat From A Multi Fuel Stove
While it’s best to keep the heat output from a multi fuel stove under control to maximize the total heat output from every piece of fuel used, getting the most amount of heat at any given time from a multi fuel stove requires sacrificing efficiency to produce maximum heat.
Getting the most heat from a multi fuel stove requires keeping the fuel topped up, while increasing the supply oxygen to burn through the fuel as quickly as possible to produce the most amount of heat.
To maximize the heat output from a multi fuel stove, large and dry hardwood logs should be used, while ensuring that that the maximum amount of wood is placed within the stove without overloading it.
When burning wood, the secondary air vent should then be opened up more to increase the supply of oxygen to the fire and to match the amount of fuel within the stove. With a greater supply of both fuel and oxygen, the fire will rapidly burn through the fuel and produce greater amounts of heat as a result.
In doing so, we were able to get our multi fuel stove up to high temperatures and producing a huge amount of heat for the room, and you can find out how hot we got our stove here.
How To Keep Glass Clean On A Multi Fuel Stove
Many models of multi fuel stove come with what’s known as an air wash system that helps to keep the glass on the stove door clear throughout the duration of the fire.
Byproducts from a fire can be deposited on the inside of the glass and obscure the view into the stove. An air wash system provides a supply of cooler air down the inside of the glass and helps to prevent soot from settling on it.
Air wash is typically provided as part of general airflow into multi fuel stoves. On our multi fuel stove, the secondary vent provides the air required for the air wash system, and so ensuring that this air vent remains open for the duration of a fire helps to keep the glass clean.
Burning low moisture content wood and having hot fires also helps to keep the glass clear.
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Secondary Combustion In Stoves Explained