How To Prevent Over Firing

What does “over-firing” my stove mean?

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. 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 blog 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 and cracking 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)

Red Discolouration Is An Indication of Over-firing
Flue discoloration is an indication of over-firing

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.

Any surface of your installation appearing red-hot is reason for alarm – for this to occur, the temperature will have been excessively high for a significant length of time and will need to be reduced.

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 stainless 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.

Charnwood Flue Pipe Thermometer

Types Of Wood

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 below 20%. You can purchase a moisture meter to check. in addition, the thermometer is an 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 try Blue Gum or Black Wattle as an alternative.

Down in Cape Town, some folks burn ‘Vine Stompies’. 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.

Preventing Overfiring

As with most things, preventing the issue is much better than having to deal with the consequences it brings. Always burn responsibly, follow the manufacturer’s instructions, and keep your installation well maintained to prevent issues occurring.

  1. Use a stove that is suitable size for your home where its heat output is sufficient to warm the room. Visiting Metelerkamps and discussing your needs will ensure you get the appropriate size stove to suit you.
  2. Operating your appliance according to the manufacturer’s instructions will greatly help you maintain a safe, clean, and efficient burn. Using the vent controls to control the airflow/heat for example.
  3. Only refuel your stove when it is necessary: when your fire is reduced to glowing embers.
  4. Regularly get your stove serviced by our servicing team at Metelerkamps. They will identify and rectify any faults that may be present in your installation and causing your appliance to overfire or underperform.
  5. Use an appropriate amount of Ready to Burn firewood to ensure you are getting an optimal, clean, and efficient burn – rather than overloading your stove with wet, unseasoned wood.
  6. Regularly maintaining your stove and getting your chimney swept by our servicing team will keep your installation functioning efficiently and safely, preventing issues that cause overfiring.

 

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. Some stoves (inc some Charnwoods) allow for burning Anthracite which burns for longer periods than wood.

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.

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!

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