Review of Woodwarm Fireview 6KW Flat top stove
WOODWARM 9kw DOUBLE SIDEDThis was installed in 2011 and, although efficient, has given us problems. We are careful and only use recommended solid fuel and well seasoned wood 1. The glass on both doors quickly became opaque. It didn't crack or break but simply became 'crazed'. The glass was replaced at some expense this year with exactly the same effect. We must be doing something wrong - but what? Any ideas? 2. We are least impressed with the function of the operating handle. What an infuriating thing! If it's turned gently clockwise it is difficult to return to its original position due to small bits of fuel becoming stuck both between and at the end of the bars so that the bars cannot be closed properly. We prefer to use an old fashioned poker!! This stove seems to have such positive reviews that we can only assume that we are the weak link. Any advice anyone?
Stove expert replied: Crazing of the glass: Explanation of the phenomena of “Crazing” in Glass Ceramic Materials: During the combustion process, fossil fuels evolve combustion by-products. These vary both in their composition and concentration, and are heavily dependent on the composition of the fuel being used, and the burn conditions within the appliance. One of the most reactive combustion by-products found is sulphur. Under certain very specific conditions, it is possible to set up a combustion environment where a chemical reaction between the glass ceramic and sulphurous deposits, which attach themselves to the glass surface (through condensation), can take place. Initially, this may manifest itself only as a series of white deposits on the glass (which can be cleaned off with ease). However, if these deposits are left on the glass surface over a prolonged time period and subjected to repeated thermal cycling in non-ideal burn conditions, an effect known as “crazing” (fine cracks appearing in the combustion surface of the glass ceramic window) can occur. However, the necessary combination of effects required for this phenomenon to arise in the first place, makes this a very rare condition indeed. As the chemical resistance of all glass ceramics, falls within a very narrow range, the solutions are limited here. In extreme situations, one can look at the potential of using a high acid resistant glass such as Borofloat, however factors such as thermal shock, really need to be carefully considered before this option is considered. Factors to be considered for minimising “Crazing” in Glass Ceramic Windows: In-Use Guideline’s - Minimise the use of high sulphur content fuels - Ensure glass ceramic windows are regularly cleaned using approved (non-abrasive) materials, and any residues are completely removed prior to use Appliance Design Guidelines - Create an effective “air-wash” across the glass - Maintain the inner glass panel surface to temperatures of 250 – 320°C - Limit the use of out-gassing materials in the appliance construction
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