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What is a load limiter?
Along the top of the fire chamber is a load limiter, which is designed to restrict the operator from overloading it. This will burn off in approximately 3-7 years depending on frequency of use. The load limiter does not need replacing but the airtubes will.
What can I do if my wetback develops a thick coating on it?
The wetback can develop a coating of crusty creosote when the wood fuel is not being burnt in the most efficient way. Firewood can play a major role in the performance of a wood fire. The species is part of the picture but the most significant thing is that whatever the type of wood it must be well seasoned and dry. Best performance cannot be achieved without the best fuel.
So back to the question...
Burning wood at low temperature causes incomplete combustion of the oils in the wood, which are off-gassed as volatiles in the smoke. As the smoke rises through the chimney it cools, causing water, carbon, and volatiles to condense on the interior surfaces of the chimney flue. The black oily residue that builds up is referred to as creosote, which is similar in composition to the commercial products by the same name, but with a higher content of carbon black. Over the course of a season, creosote deposits can become several inches thick. This creates a compounding problem, because the creosote deposits reduce the draft (airflow through the flue) which increases the probability the wood fire is not getting enough air to burn at high temperature. Since creosote is highly combustible, a thick accumulation creates a fire hazard. If a hot fire is built in the stove or fireplace and the air control left wide open, this may allow hot oxygen into the chimney where it comes in contact with the creosote which then ignites—causing a flue 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. The build-up around the wetback is best removed by hand and the rest can be carefully removed by a vacuum cleaner.
The wetback can be knocked out of alignment if it is moved when the creosote is being cleaned off. This can cause the constant rise to be knocked out of alignment and can result in water hammer developing in the system so be careful. The wetback can develop a coating of crusty creosote when the wood fuel is not being burnt in the most efficient way. Firewood can play a major role in the performance of a wood fire. The species is part of the picture but the most significant thing is that whatever the type of wood it must be well seasoned and dry. Best performance cannot be achieved without the best fuel.
Why have Pyroclassic fires dropped from No. 1 on Consumer NZ tests on their last report?
Consumer Magazine recently changed the way fires are rated. This has caused some issues across the industry as what were considered the 'best' fires are now not rated near the top...like the Pyroclassic IV. They have changed the weightings of their review to focus more on price for output over emissions and efficiency as they believe this is more in line with what the customer wants.
This has resulted in a list which is more about heat output for dollars spent rather than which fires actually perform the best. It also makes no provision for servicing costs, warranty duration or expected life of the appliance and its components.
The statement we have printed in our marketing material - 'Consistently chosen as the top pick for wood fires in all Consumer reviews' refers to the consumer reviews across various formats in NZ, Australia and the UK over the last 30 plus years including true consumer feedback.
Why is the door glass small?
Big door glass = big waste of heat
Glass is a very poor insulator, which is not ideal when it comes to wood fires!
The original Pyroclassic fire did not even have a glass as the scientists wanted the fire to be as efficient as possible. Over time, consumers expressed their desire for a window into the fire which has resulted in the glass getting larger with each version.
The Pyroclassic IV has the largest door glass that can be fitted to the front of the fire as the glass retaining strips fit just inside the front opening of the fire chamber.
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.
How do I remove the ash from my Pyroclassic?
Remove the ash when the fire chamber is relatively cool. Use the Pyroclassic curved shovel to slowly empty the fire chamber. Ash almost always contains some hot ember.
Never use a vacuum cleaner. Obtain a metal (non-combustible) ash container with a lid. Store outside on concrete or bare ground.
Pot ash can be great for your garden if your soils are acidic, use only ash from a cooled fire which used good quality wood.
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.
What size firewood should I be using in my Pyroclassic Fire?
Logs should be approximately 100- 120 mm 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.
The room or space containing the Pyroclassic needs no additional ventilation unless a draught stabilizer is fitted, in which case a permanent opening of at least 1500mm2 should be provided. Any air opening must be kept clear from blockage and obstruction. Due consideration should be given to air requirements for any other appliances in the same room or home, such as heat transfer kits, kitchen range hoods, laundry dryers, bathroom vents etc.
If your fire has been installed into a new build home, these are constructed to be far more air tight than older housing can have an significant impact on the free air available over time to the fire, especially when other forms of mechanical extraction from within the home are used such as range hoods, dryers, wet room extraction etc. In severe cases the flue pipe can actually end up being used as the means of ventilation causing the flue gases to then be drawn into the house. This is not a fault of the fire but a flaw in the inadequate ventilation planning of the house construction and NZ building code.
A further point of note on the house topic is the location of the house in relation to its surroundings and the termination of the flue system, this is often referred to as downdraft.
How much does it cost?
To download the RRP price list of our Pyroclassic wood fire and accessories, click HERE.