Click on the heading of the article in red to open the full article.
How should I store my wood?
Gathering and stacking wood in the open air over the summer period is advantageous because the warmth of the sun and good air circulation will automatically evaporate some of the sap. When the wood gets wet from seasonal rain, the rain water replaces sap and because water is more quickly evaporated, the fuel dries faster.
Split larger logs, so that the largest surface area of the internal wood is exposed to the atmosphere, stack the wood loosely, on bearers, with the ends facing a prevailing wind, cover with a plastic sheet on a light frame to create a warmhouse effect, with the sides open to the prevailing breeze so it can flow freely through your stack.
Do not use it until it is fully seasoned, do not stack rotten wood - it has very little useful heat in it and leave the bark on split wood - it helps to provide natural protection from rain.
When and how should I clean the flue?
Pyroclassic Fires are renowned for burning very cleanly when dry fuel is used but you should still always clean your flue once a year. This is often a requirement for many insurance companies.
Keeping your flue pipes clean will help eliminate the risk of a flue fire. Your flue is also a great indication of how your wood fuel is performing. If the pipes are clean then the wood is good, if the pipes are filling up with carbon, creosote and tar deposits then you may need to revisit the operating instructions and refresh yourself with how to create a cleaner burning fire.
The easiest way to clean the flue is by placing a deep baking tray or similar under the base of the flue and sweep the flue down into this, this stops all the debris from falling into the top chamber and requiring vacuuming out. Sweeping the flue into the top chamber is never a good idea as it can restrict the flow of gasses from the primary fire chamber and cause your fire to perform poorly.
To clean the top chamber and wetback, you will need to remove the top plate (it just lifts off) and clean out the top chamber of soot and creosote. Take care not to remove any of the Kaowool lining during cleaning and ensure that the gasket is all intact before replacing the top plate. Support the flue with a frame made of wood so you can easily remove the top plate.
The build-up around the wetback is best removed by hand. The wetback can be knocked out of alignment if it is moved when the creosote is being cleaned off so be careful as this can cause the constant rise to be knocked out of alignment and can result in water hammer developing in the system.
What is the best type of wood to use?
A number of things should be considered when using wood for heating. An understanding of the various types of wood fuel that is available including its advantages and limitations, and it is essential to know how to light and maintain a good fire.
Wood fuel ranges from soft woods like pine, to hardwoods like manuka. But whatever wood is chosen, the key to a successful fire is to ensure the fuel is as 'Dry', or as 'Seasoned', as possible.
Green wood can hold up to its own weight in moisture and sap and it takes time to get rid of this.
While surface water does not really matter because that will evaporate quickly, it is important to reduce the sap levels within the cell structure of the wood itself. Softwoods will season quite quickly, in about 6 to 12 months, but it can take for 18 months to 2 years for hardwoods such as Manuka to dry to an acceptable level.
Most woods make suitable fuel, pine is common and good its high resin content and loose cellular structure means it burns faster than some others, so be prepared to make more trips to the wood shed. Macarocarpa and gum are also excellent fuels although marcarocarpa tends to spit and spark more than a lot of other fuels and in some appliances this may cause servicing problems because of fly ash.
It is suggested avoiding native timber for fuel, unless it becomes available through demolition or natural attrition. Manuka though, is considered a nuisance timber in some areas of New Zealand, and could be used for fuel. It is indeed good fuel - provided it is dry - but remember, drying Manuka will take a long time.
If you knock two pieces of seemingly dry wood together if it "rings" rather than "thuds" it is likely to be dry, regular use of a moisture meter will ensure you know just how dry your wood fuel is. However simply because a piece of wood is dry on the outside, it doesn't mean that it is dry enough to burn. Conversely, even if the outside is wet, if it is seasoned properly, it will often burn beautifully. The drier the wood, the cleaner the burn, the less likely is creosote formation and unburnt smoke being exhausted from the flue.
Place a piece of timber on a good fire base if three sides are burning within 15 minutes, the fuel can be considered to be "dry."
How do I clean the outside of the Pyroclassic and the flue pipes?
The powder coated panels on the Pyroclassic IV can be wiped clean with some light detergent and warm water. You can choose to do this with the panels on the fire or remove them for a more thorough cleaning. Be careful when you remove the front panel to not tear the insulating gasket which is on the inside of the panel: you will need to pull the centre of the panel forward slightly to allow it to clear the space behind it when you slide it up.
The stainless steel flue pipe can be cleaned using a soft cloth with a small amount of methylated spirits soaked into it. Try to avoid touching the flue pipe with your bare hands as this leaves oils from the skin on the pipe and becomes very hard to remove once the pipes have been heat cycled.
My fire is slow to start up. What can I do?
- Open the Turboslide by moving it to the far left or right position.
- Check the start-up hole is free of ash and char on the inside, push back any build-up with the rake. The start-up air supply hole allows air to enter the fire chamber like a pair of old fashioned bellows, if the hole is clogged with ash and char it will not work.
- Check for air leakage around the cook top, around the flue collar and in the flue pipe joints. Air bypassing the fire chamber reduces draft. Repair any air leaks.
- Slow start up can occur if you are fueling the fire with large or wet logs or loading onto too few hot coals. Use dry kindling to start fire quickly. DO NOT USE WET FUEL.
- Insufficient draft. Review chimney construction and investigate air pressure levels in the home.
- Warm, humid conditions outside or an inversion layer. Wait until the flue pipe heats-up.
What are the National Environmental Standards for Air Quality?
The National Environmental Standards for Air Quality (NES) are regulations made under the Resource Management Act 1991 which aim to set a guaranteed minimum level of health protection for all New Zealanders.
The NES came into effect on 8 October 2004. They are made up of 14 separate but interlinked standards.
- Seven standards banning activities that discharge significant quantities of dioxins and other toxics into the air
- Five standards for ambient (outdoor) air quality
- A design standard for new wood burners installed in urban areas
- A requirement for landfills over 1 million tonnes of refuse to collect greenhouse gas emissions
What does it mean by the Pyroclassic being 'Self Regulating'?
The vigorous fire near the loading door automatically slows down as the burning front advances through the firebox towards the back. Each cycle ends with ash and hot ember at the far end of the firebox. Only use the Turboslide when lighting, adding fresh fuel or if you quickly want a very vigorous fire. The Pyroclassic® IV not only provides heat soon after start up but it also stores a lot of the heat from burning your wood, you will get most of this heat back over several hours. Frequent reloading may result in high room temperatures but you will soon know how much and how often to add fuel, the best heater output control is how much and how often you do this. The Pyroclassic® IV is designed to save on firewood and to keep emission levels to the minimum by storing the surplus heat which normally goes up the chimney - this heat is still being released into the room even when the fire is low at the end of each burn cycle.
What wood should I be using?
DRY. This means a maximum of 25% moisture content but ideally under 18% if possible.
Do not burn any wood which has been treated as this will release poisonous gases and dioxins. Do not use any driftwood as the salt content can cause irreparable damage to the ceramic cylinder and metal components. Younger softwoods and timber which has a higher moisture content will produce a greater volume of creosote and soot than dry, well seasoned hardwood.
Logs should be approximately 100mm - 120mm in diameter by around 300mm - 400mm long for your Pyroclassic IV Fire. Logs should be approximately 100-120 mm in diameter by around 200-250mm long for your Pyroclassic Mini Fire.
Dry wood is a must. To get the heat out of wood the fuel must pass through several stages. Firstly, free water that is not chemically bound with the wood is driven off – even wood at 20% moisture content still has to get rid of 2 litres of water for every 10 kilograms of wood. In the second stage the wood breaks down into the volatile gases, liquids and charcoal. Finally, the charcoal is also gasified, burning with a very short flame close to the char surface that appears to glow. In wood stoves all stages proceed simultaneously.
Wood is the most prolific worldwide, solar embedded, carbon sequestered energy source which is renewable in a human lifetime. It will provide energy when the sun is not shining and the wind is not blowing, when the outside temperature is above or way below freezing and when the electricity is not coming out of that little hole in the wall. If the abundant, worldwide timber resource is managed correctly it is the most sustainable, environmentally safe, renewable, resource we have and it has sustained mankind for centuries, providing us with warmth for the space we live in, warm water to clean with and the ability to cook food.
With the discovery of more energy intensive and easily transportable fossil fuels, wood was relegated to a lowly place in the order of preference and although it is bulky to transport it is the safest as it does not need a specially built pipeline, it won't suddenly explode or cause devastating marine pollution and with almost no refining can be used in its raw state. The closer it is used to the place where it has grown makes this an even more environmentally friendly product.
Most designer wood burners catering to aesthetic demands totally disregard the thermal conductivity of wood. Microscopic examination of wood shows the channels which carry the liquid nutrients up and down the tree; consequently the properties of wood are very different along the grain than across it. Heat moves along the grain about fifteen times faster than across it, therefore, solid wood across the grain does not conduct heat and is an effective insulator meaning it does not readily burn.
When a fire is lit, even by rubbing two sticks together, the gasification process starts and it is the combustion of these gases with air that produce heat which we see as flames and smoke. When heat cannot penetrate wood easily, i.e. across the grain, the volatiles given off are not rich enough nor hot enough to burn efficiently. Efficiency apparently is not a consideration in such panoramic appliances.
This is getting to the really nerdy bit now...
Burning of the volatile gases delivers over 60% of the heat stored in the original log but few heaters can recover the major portion of this heat as the volatiles must be over 600°C and mixed with hot oxygen to burn them. Now these are difficult conditions to meet and here’s why: if the main air supply comes from under or around the burning logs, the glowing char consumes all of the oxygen - it takes only 5cms of glowing char to consume all the available oxygen. At that point, incomplete combustion continues as characterised by increased carbon monoxide and tars which mostly go up the chimney where the unburnt volatiles deposit on the flue walls as a highly flammable, gummy substance known as creosote. It is wrong to introduce cold secondary air above the fuel as it cools the gases below their ignition temperature and now they won’t burn at all. The requirement is to introduce a highly pre-heated but variable volume of air for the different stages of combustion. This is done very efficiently by the secondary air tubes inside the Pyroclassic IV fire.
All fires consume large volumes of air in order to extract the oxygen required to burn their fuel. One kilogram of wood needs 3.7m3 of air to burn completely, although this is only a theoretical minimum for stoichiometric combustion. Such ideal combustion does not exist in real life as only some of the oxygen in that amount of air can be used and therefore 'cool fires' need some 200% - 300% excess air to get the oxygen they need. Therefore some 7 - 10m3 of air per kilogram of wood pass through the firebox cooling the core temperature inside it and cooling air below 600°C , which kills the reaction needed to burn the volatiles. In most fires the air needs of the fire make it work against itself making it inefficient and polluting, the excess air it uses only goes up the chimney with all that gas, tar and particulates. A Pyroclassic IV only uses super-heated air in its secondary burn cycle ensuring there is no cooling of the firebox and no excess air consumed.
Burning wood scientifically is done very effectively by the Pyroclassic IV freestanding woodburning fire but even the cleanest and most efficient woodburning stove needs logs which are as dry as possible to give the best output from your fuel. Check the moisture content of your wood when you buy it and then let nature do the hard work for you. Stack it off the ground in an open sided, roofed store to allow plenty of air flow around it for as long as possible or at least until the moisture content is below 20%. It’s then ready to be used in your Pyroclassic fire to give you a nice warm house right through winter in the most efficient and cleanest way possible.
Can I install a second hand wood burner?
We recommend you discuss your plan to install a second-hand woodburner with your local city or district council or the unitary authority in your area before purchasing the woodburner. There are factors in addition to the National Environmental Standards for Air Quality that these agencies need to consider before permitting the installation of a second-hand woodburner.
See more information at http://www.mfe.govt.nz/air/national-environmental-standards-air-quality
Why is smoke coming from my Pyroclassic fire into my room?
There are a few reasons why this could be happening:
- Negative pressure in the room - this can be caused by a household electric exhaust fan or severe pressure difference in a windstorm. Open a window to equalise the pressure.
- Severe down draft due to surrounding structures, hills, trees or roof layout.
- Most commonly, this is an indication your flue is blocked. Clear the obstruction and investigate the cause. Check the moisture of your wood and make sure you are burning good, dry wood. The flue pipe can block very quickly if you are burning wet or gummy wood. Make sure you are using a reliable chimney sweep as the Pyroclassic is different from other wood fires.
Download down draft troubleshooting info HERE.