Guidelines for using Wood log Fireplaces 

ONLY USE DRY SEASONED WOOD IN YOUR FIREPLACE

It is critically important that the wood used should be dry and well-seasoned (cut at least a year in advance and left to dry). It should have a moisture content of less than 15%. 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 firewood will result in oxidation (rusting) of metal components in the structure of your fireplace and potential damage to materials.

Wet/fresh wood will make it very frustrating to use the fireplace and gives poor heat output.

Dry/seasoned wood will make the fireplace easy to use and gives high heat output.

We recommend that you buy wood from a reputable and responsible firewood merchant. Wood from sustainable plantation are recommended.

 

MEDIUM-DENSITY HARD WOODS

We recommend using medium-density woods like Blue Gum and Black Wattle as these woods are easy/safe to use in closed combustion fireplaces.

They don’t burn too fast and also not too slow.

However, wood suppliers in SA often run out of stock of these dry seasoned woods in winter and customers look for alternative options.

 

EXTREME HARD WOODS

Local hardwoods like Kameeldoring (Camelthorn), Sekeldoring (Sickel Bush) and Mopane have very low moisture content as they have dried naturally in the desert. They are also very dense (in the top dozen hardest woods in the world), releasing more heat per log and burning at very high temperatures.

To avoid overfiring your fireplace and causing damage, do not overload.

These woods produce an orange, long-lasting coal, extending the time needed between loads.

These hardwoods can be used on their own in fireplaces with ceramic internals, as the ceramics keep the fire chamber at a very high temperature that burns the wood easily (good flames, not much smoke, high heat output).

However, in the cast iron fireplaces (without ceramic internals) these very dense woods may burn less easily (this results in more of a smouldering fire with less flames, more smoke and insufficient heat output).

We therefore recommend using a 50% mix of the hardwood and a medium-density wood (or kindling) in the cast iron range to achieve a good fire with high heat output.

Important to Remember:

Buy wood from a reputable firewood merchant and ensure that the wood is dry, seasoned wood.

Do not burn coal or any other material in fireplace.

 

Important to remember:

  1. The first few times that you light your new fireplace use a half load of firewood. The paint on the fireplace needs to cure and the fireplace needs to settle.
  2. The first time that you light your new fireplace there will be a hazy smoke and unpleasant smell from the excess oils of the fireplace burning off.
  3. Make sure fireplace is clean before starting a new fire.
  4. Make sure air intakes are open.
  5. Keep door closed when running the fireplace.
  6. Use a heat glove when adding wood.

 

STARTING THE FIRE

Make sure that the ash box is cleaned empty.

Make sure that the glass door is clean.

Make sure that the air intakes are set to open position.

To start the fire, use 2 pieces of log wood with a good amount of kindling wood (thin pieces of wood) stacked on top. Use fire lighters to light the kindling wood. The thin kindling wood will light easily. This kindling fire will light the larger log wood. Add more log wood when the fire is burning well.

Only have the glass door open to add wood briefly.

Use a glove when adding wood. This will prevent splinters in hands and also offer protection against the heat from the fireplace. Without a glove, a person will tend to sometimes drop wood into the fireplace, which can cause damage (especially to ceramic internals of fireplace!). You can purchase a set of leather welders gloves from a hardware store.

 

RUNNING THE FIREPLACE

It is far better to control the fireplace if you rather load your wood periodically, one good size load every hour as apposed to smaller amounts of wood at regular intervals.

Once your previous load of wood has burnt down to a good amount of glowing orange coals then spread these coals across the bottom of the fireplace chamber. Add your new load of wood on top of the glowing coals. The size of your load of wood depends on the heat output that you require and the heating capabilities of your fireplace (see table below for guide).

Once the new load of wood is starting to burn well then close the air intake controls to the point that you have a controlled lazy flame. With this lazy flame your fireplace is operating at a high efficiency (as apposed to with the air intakes completely open and a forceful flame that indicates less efficiency levels for the heat sent into the house).   

Table of wood log load per hour

Load per hour of 1kg logs

Heat output (per hour)

2 pcs of wood

6 kW

3pcs of wood

9 kW

4pcs of wood

12 kW

5 pcs of wood

15 kW

6 pcs of wood

18 kW

7 pcs of wood

21 kW

8 pcs of wood

24 kW

Table considers that the wood is dry (below 20% moisture content)

Table considers that the wood is loaded once per hour and burning up to be replaced with a new load

Table considers that the one log of wood weighs about 1kg

Table considers that fireplace is operating at around 80% efficiency

 

For the above table - If you are using a harder wood that takes longer to burn, so that you are loading wood every say 90 minutes, then to achieve the same kW output you will need to increase the pcs loaded per 90 minutes by 50% to account for the longer burning time.

 

CERAMICS

Some of our steel range of fireplaces have ceramic internals called Acumotte ceramic. These are highly refractory ceramics that send an intense amount of heat through the glass door into the home. The ceramics raise the temperature of the combustion chamber to offer more efficient combustion.

This intense heat burns soot off the glass and helps to keep a clear beautiful view of the fire.

The ceramics have excellent thermal properties and can withstand higher heat than the fire will reach. They can however be damaged by impact. Therefore, make sure that heat gloves are always used when adding wood so that you will be able to delicately place wood in the fireplace with no chance of dropping wood against the ceramic. Also, be careful not to use a metal stoker in the fireplace.

It is normal to have slight flaking and chipping of the ceramics around the areas where the wood is in contact with the ceramic.

If a slight crack has been noted on the ceramic lining (e.g. the so-called hairline cracks), this is not a reason for its immediate replacement Acumotte does not lose its properties. It still functions in the same way and has no negative impact on the combustion process. Remember, however, that the lining cannot be punctured to allow open gap to the steel body (in this case, Acumotte should be replaced).

The ceramics are long lasting but will eventually need to be replaced after several winter seasons depending on use and care taken.

 

FANS

The fireplaces that have fans are thermostatically controlled and the control button (bottom right inside of glass door) can be left on the “0” position. At this position the fans will turn on when the fireplace is getting hot (about 30 minutes after starting fire). The fans will also automatically turn off when the fireplace cools down (sometime after the fire is out). The fans also have power control positions “1” and “2”. This is for manually adjusting the fan speed. Speed 2 is maximum fan speed. Speed 1 is slow fan speed where the fan sound is quieter. 

 

GLASS

The glass door on your fireplace is the most expensive part of the fireplace to replace so please take care with it to avoid expensive replacement. Depending on the fireplace model, the glass can be from R 1 000 to around R14 000.

The glass door is able to withstand heat of 800 degree Celsius (higher than the fire can reach). However, if you don’t clean your glass and layers of soot can build-up over time on the glass which can eventually ignite and cause the glass door to crack.  Also, be careful with impact not to damage the glass door.

 

SERVICING THE FIREPLACE

It is recommended that to prolong the lifespan of the fireplace, that the fireplace is serviced annually, preferably at the end of each winter. This service should be done by an experienced fireplace technician that will have the knowledge to check the fireplace thoroughly. The technician should also give attention to the metals of the fireplace with the correct protective/care metal polish products.

 

Overfiring

Overfiring is the single fastest way to significantly shorten the life of your fireplace.  Each fireplace comes with a recommended amount of wood to be used per hr. There is a table at the back of the instruction manual. This amount of wood should be monitored depending on your fireplace, as over-filling your fireplace with wood would result in temperatures that are over the design limits. The warranty does not cover for damages where overfiring has been reoccurring for a long period of time.

What causes a stove to overfire?

  • An excess of oxygen or fuel is the cause of a stove overfiring.

The three components of fires are: 

OxygenFuel and Heat.

 Increasing any of these 3 components will increase the intensity of the fire.

Having too much wood or a lot of air flow can also cause it to overfire, as these factors can increase the amount of oxygen and fuel.

 Loading your stove with too much wood will give off an excessive amount of fuel, this creates a runaway burn, that gets uncontrollably hot while also blocking main tertiary air vents and preventing secondary burn of gases.

Too much air flow feeds your fire too much oxygen, that will cause it to burn excessively. Leaving the stove door open, not using the air vent properly or deteriorated rope seals is the result of excessive air flow.

With extremely hot temperatures, one or more of the following can occur:

Metal on the inside of the fireplace turns reddish color and starts flaking.

  • Metal components inside bend out of shape.
  • Baffle plate is prematurely worn out or warped. Units will have a strong chemical or steel smell when burning.                                                                                      
  • Flues will discolor to a dark copper color close to the unit.                                                                                                      

Chimney fire risk heightens due to the temperature of the gases in your flue increasing, causing any residual debris – such as soot or creosote – to have a higher likelihood of igniting and causing a chimney fire.                                                  

Damage may occur to the wall, furniture or materials around the stove.

 

Safe Installtion of your Fireplace 

A good flue kit consists of both insulated and plain flue pipes, which is the industry standard. The flue piece which connects the plain flue pipe with the insulated flue pipe is called an insulated “end-cap”, and this item of the flue kit is installed about 300mm below ceiling level, and runs into the roof space.

The reason that we use insulated flue pipes when going via your ceiling and roof is because single skin flues get really hot. Single skin flues help to heat your house and serve as an extension of the fireplace. However, an insulated flue is the best choice for when the flue goes through your ceiling, roof space and exits via your roof itself, because an insulated double skin flue only gets warm and this is much safer. In this way your waterproofing will be more durable as the outside of an insulated flue pipe will not expand and contract upon heating and cooling down like a single skin flue pipe. Lastly, an insulated flue will vastly decrease the build-up of condensation within your flue, as the insulation prevents the hot smoke from cooling down too quickly. It is therefore preferable and safer to use insulated flue piping once the flue pipe leaves the interior of the room that is being heated.

The standard choice of material is anti-corrosive, 304 stainless steel. This will guarantee many years of safe usage of your fireplace and flue kit.

All flues are made from superior 0.4 mm thick, 304 grade Stainless Steel, which is suitable to withstand the effects of long term corrosion by the harsh chemicals within the flue gases of closed combustion fireplaces. These flues are seam welded and utilise a clamp method of assembly. We therefore avoid drilling and pop riveting.

Please note that all stainless steel flues discolour overtime, due to a natural chemical reaction caused by exposure to 02 in the air and the heat from your fireplace. This natural reaction creates ‘living art’ in your home, as the colours range from golden to amber, even purples and blues, depending on how hot your fireplace is fired.

If you’d prefer something other than a ‘stainless steel look’, then you can choose to have your flues sprayed in the same colour as your fireplace i.e. black, anthracite grey, or Ivory. This is done at an additional fee and needs to be pre-ordered with your fireplace. Feel free to enquire about this when requesting a quote.

 

Contact Us

Info@caldofires.co.za

Whatsapp: +27 84 519 7912