General Fireplace Guide

If your fireplace has been successfully installed to manufacturer’s specification by a trained and registered Calore installer, you are now ready to use your appliance for the first time.

The information below will assist you in answering the following generic “how to questions” and quickly help you along your way to a warm and cosy home.

How to choose your wood


It is of crucial importance that the wood you burn should be dry and well-seasoned, with a moisture content of less than 20%. Unseasoned wood contains a great deal of moisture, which reduces the burning temperature of the fire and causes additional smoke and pollutants. Excessive high moisture in your fire wood will result in oxidation (rusting) of metal components in the structure of your fireplace and potential damage to insulation and vermiculite.

Calore recommends that you buy wood from a reputable and responsible firewood merchant. Wood from sustainable plantation are recommended. Please ask your local Calore outlet for the contact details of a reputable and responsible local firewood supplier.

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.

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 and if left untended can cause a chimney fire. Creosote formation can be minimised by burning dry/ well-seasoned wood at higher temperatures.

 

Important to Remember:

               

Buy wood from a reputable firewood merchant

 

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 your local Calore Reseller

 

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 store your wood













Stack your wood loosely off the ground in a criss-cross fashion to allow the air to circulate freely (Figure 1). 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.

Figure 1: Storing wood in a criss-cross pattern allows free air flow.

How much wood should you use?


It is relatively easy to work out how much wood should be burnt in a specific kilowatt close combustion fireplace. The correct calorific value of wood can be calculated by subtracting the moisture content of the wood in question from the potential calorific value of wood in general. The answer in Kilowatt can then be used to be divided into the Kilowatt potential of the fireplace to arrive at a maximum kilogram per hour consumption rate.

As Example: How much wood should be used in a 10 Kilowatt fireplace? Let assume we are using well-seasoned wood with a moisture content of 15%.

 

5kW (potential calorific value of wood) – 15% moisture content = 4.25 kW thus…

10kW divided by 4.25kW = 2.35 kg of wood per hour necessary to achieve a 10 kW output.

! Never exceed the recommended maximum load: Exceeding the recommended maximum load may result in damage to the fireplace which will shorten its usable life span or may even damage it beyond repair.

 

! The first 5 times: It is very important to remember to use half a load of firewood for the first 5 fires in your new fireplace. The paint on the fireplace needs to cure and the fireplace needs to settle. Please do not touch any painted parts during this first 5 small fires – the paint is still curing and may smutch. If this instruction is not followed the paint on your new fireplace may start peeling off.


How to build an “upside down” fire



Step 1
– The larger logs first

Start by placing the largest logs side by side. 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.

 
Step 2 – The medium sized logs

On the next layer(s) put the medium size logs that are a bit smaller and can burn easier. The easier it is to burn, the higher on the pile it goes.


Step 3 - The Kindling

Finally the smallest pieces that is easiest to burn goes on the very top. Kindling & Tinder.

Step 4
– Starting the upside down fire

Place your eco-firelighters with-in the first layer of kindling and light it.

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 (Please see below Figure 2 for a visual illustration.

In the upside down fire 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.

 
Creosote burns as hot as coal (1000 Degrees Celsius), so its escape from the firebox is a loss of potential heat for the house. In the upside down fire, all creosote burns up in the stove or fireplace.

 
As long as you have a good bed of coals, the firebox will be hot enough to heat up and ignite fresh fuel. 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.

 

Figure 2: The upside down fire


How to control the fire?


A close combustion wood burning fireplace can be controlled by regulating the amount of oxygen that enters the combustion chamber. More oxygen will accelerate the combustion process causing more heat output and less oxygen will decrease the combustion process resulting in less heat output.

The regulation of oxygen is predominantly done via the primary air intake control – usually located at the bottom front of a close combustion unit and in line or below the combustion chamber. The primary air intake supplies oxygen directly to the wood for primary combustion.

Most closed combustion fireplaces are also fitted with a secondary air intake control. The secondary intake can be fixed or adjustable depending on the make and model of the fireplace. The secondary air intake control are usually located at the top of the door/glass of the unit and in line with the top part of the combustion chamber. 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.

 

Higher output close combustion units may also be fitted with a flue damper. A flue damper dampens (controls) the flow of flue gas and slows the amount of oxygen that enters the combustion chamber. The amount of flue gas leaving equates to the amount of oxygen entering the unit. With a flue damper control, oxygen is controlled by increasing or decreasing the flow of flue gas.

 

Oxygen control per operational stage:

Start up

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).

!Leaving the door/glass open for extended periods of time will overheat and damage the fireplace

Normal operation

Depending on user requirement – the air controls can be opened up and closed down to obtain the required heat output, fuel efficiency and effect

More oxygen – bigger flames, faster tempo of heating (higher kW output), higher temperatures and higher fuel consumption

Less oxygen – smaller flames, slower tempo of heating (lower kW output), lower temperatures and lower fuel consumption

Refuelling

Before new wood is added to the combustion chamber – open all oxygen controls fully

Slowly open the door/glass of the unit to prevent smoke from entering the installed environment

Leave all oxygen controls open until the newly loaded wood is well lit, before the oxygen controls are set lower

Night time operation/ Maximum fuel efficiency

Load the maximum allowed load of wood

After the wood is well lit – closed the primary air intake completely or as far as possible – without extinguishing the flames completely

The secondary air intake can also be adjusted down if possible

A slow rolling flame in the top part of the combustion chamber is the optimal result

Extinguishing the fire

To extinguish the fire stop fuel supply

Close all the oxygen controls


How to maintain your fireplace 

Maintenance, and servicing on your closed combustion fireplace is compulsory. Noncompliance in this regard will render your product warranty null and void.  Maintenance should be done daily in season.

 

Daily maintenance includes the following basic activities;

Removing all the ash from the fireplace

Clean the glass of the unit

 

Annual Servicing includes the following activities (Done by a Calore qualified technician);

Preparation of the work area - Protection / coverage of the work space with special covers or cartons

Unplug/disconnect the product from the electrical power supply if forced ventilation has been installed.

If possible, we recommend taking the stove outside in order to work with more freedom of movement.

Vacuum out the interior of the stove.

Use a soft brush to clean the ceramic plates.

Take the baffle plates outside with all other removable parts of the stove, brush them thoroughly with a steal brush or special sand disks for an angle grinder. Check the integrity of the different parts - if they are in good condition paint them with the special silicon paints provided Calore (front and back). Grate polish can also be used - Only applicable to cast iron.

Brush and clean the interior of the combustion chamber, while using a vacuum cleaner to limit the dispersion of dust and to reduce smell of paint in the installation environment.

Check the integrity of the door gasket and glass gasket. Clean the glass door with an appropriate product (with ammonia-based degreasing agents and not corrosive substances such as solvents)

 Unplug/disconnect the product from the chimney and clean the whole rear part of the stove, using a vacuum cleaner, if applicable.

Where an electrical ventilation system is installed, take it outside to clean thoroughly using a compressor or vacuum cleaner. If necessary replace the ceramic fibre gasket.

Using the appropriate brushes and a vacuum cleaner, clean the flue pipe. Check the integrity of the gaskets/seals of the flue pipes and replace it if necessary.

Re-connect the stove to his flue system/chimney.

 

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.