Over-firing your stove is the phrase you do not want to hear from your stove supplier following damage to your stove! Damage caused by over-firing is not covered under ANY manufacturer’s warranty.
However, any decent stove should last you a lifetime provided it is maintained properly and used correctly. Yes, some internal components will wear out – that is just the nature of the product – but the main body of your stove should last you decades.
So how can you avoid over firing your stove and so avoid costly and unnecessary repairs or even replacement of your beloved fireplace? In this article we provide some valuable guidance.
What is over-firing?
Simply put, it means burning your fuel too hot, thereby running the stove’s temperature hotter than it is designed to handle – hotter than the materials of the stove can take.
What will happen if I over fire my stove?
Damage will be evident in warping of the throat or baffle plate of your stove. The throat is situated directly above the bed of the fire (above the fire grate).
If left unchecked, over-firing will result in burning through the grate itself prematurely. This will warp the materials the grate is made from. If not repaired, you will end up warping the body of the stove, something that cannot be fixed.
How do I know if I may have over-fired my stove?
Check the shape of your throat plate above your fire bed. If it is starting to bend or has dropped out because it has warped, even though you have only used your stove for a couple of seasons, then something needs to be addressed.
Also, if your throat plate (baffle plate) is steel in construction and you notice red discolouring on the steel, this may also be an indication of over-firing (see image below).
One benefit of a good steel throat plate is that it is possible to straighten the plate, as long as you have the tools and/or muscle. You cannot do so with a cast iron plate. Other indicators of over-firing may be white discolouration on cast iron stoves.
How do I avoid it?
The easiest way to avoid over-firing is to fit a thermometer to your flue pipe. They can be attached quite easily (either magnetically or with a stainless steel rivet if your pipes are Grade 304 steel). The thermometer will tell you what is going on in terms of temperature, and has guidelines to help you keep your fire in check.
Certain fuels (particularly wood) will burn hotter than others. If you burn tinder-dry wood that generates large flames, you may need to monitor your temperature more carefully. Generally, stove manufacturers recommend a moisture content of around 20%. You could purchase a moisture meter to check this but frankly, the thermometer is a cheaper and much more effective way of monitoring at what heat your stove is operating. If you find that wood like Namibian Hardwood (Kameeldoring) is generating too much heat, then one option is to try Blue Gum or Black Wattle, which may burn slower and will not generate such large flames.
Down here in Cape Town, some folks burn ‘Vine Stompies’. I have burned these on my BBQ (Braai) and their flames rage, as they are very dry and lightweight. For this reason we would personally not recommend these for use in your stove, for fear of the risk of over-firing.
My stove does not feel hot enough now that I am not ‘over-firing’ it. What can I do?
Aside purchasing a bigger stove (your stove supplier should have checked your requirements), you can try running your stove slower but for longer periods. That is what stoves are generally designed to do. Light it earlier in the day so that the heat can soak in to the room gradually instead of trying to get fast, intense heat. If you have a really good stove (like a Charnwood) you can mix some Anthracite in for longer burning time while you are out.
If you have your stove set inside a chimney breast or in a room with a high ceiling, you can try using a stove fan to encourage heat radiation forward into the room, rather than allowing the heat to just float straight up. See our products page for more info on the quality stove fans we offer at Island Fires.
Whatever you choose to do, we strongly recommend that you do not continue to fire your stove harder that it is designed to handle. You can then enjoy longer life from your stove, without the added expense of repairing damage from over-firing!