Cracked glass on my Jotul woodburning stove
Hi all. We have a Jotul F400 that was installed in December 2005. We burn it pretty much nonstop from November through March. We've had an unseasonably warm spell and did not burn the stove last week. I went to clean the glass before lighting it yesterday and noticed that the glass had a crack in it, maybe 3" long, extending upwards at the bottom center of the glass. I called the place where we bought it and they said it was safe to burn with the crack, as long as the glass was still intact and no pieces were actually broken out of it. They offered to order new glass for me but it will cost $102, plus I have to install it myself (or pay another $49 if I take the door to the store to have them do it, and $129 if I have them come to the house to install it). I figured that if it was safe to burn, we'd just wait til the end of heating season to replace it. However, we've had it burning since yesterday and this evening, the crack got much longer - it is now an upside-down U about 4" high and 4" wide at the bottom of the glass.
I have NO IDEA how the glass got cracked - we hadn't done anything differently. We do occasionally have logs fall against the glass but I never cram stuff in and shut the glass against it. There was a bit of creosote on the bottom part of the glass, which means the last burn was a low smokey overnight one where the logs were probably pretty close to the glass -- but that's pretty much what we do every night. That night we had more creosote than normal, which I think was due to the fact that the last wood I used wasn't quite seasoned enough.
Does anyone have any experience with cracked glass? Is it really safe to burn this way or should I stop burning til we get the replacement glass (will take about a week and a half, which will be a significant ouch-er on the oil bill). And does anyone know what cracked the glass in the first place? I really don't want to have to shell out $102 for new glass on a regular basis! Thanks!