Fireplace Xtrordinare Help

[TulsaOK]

i have three Fireplace Xtrordinare's in two different homes, one of them works great, the other two completely char the glass on any burn that is less than fully open air inlet. My wood tests dry and I use the same wood in the house that has the two where one works and the other doesn't. I have had the installers out to look at them on multiple occasions and they can't seem to find anything wrong with them. I really like the heat, but two of them might as well have no glass because you can't see through it at all. The only way to keep the glass clean is glass cleaner, bar keepers friend, and a lot of scrubbing every day.

All three seem to draft well and I can see the catalytic converters are igniting and working well. Any ideas or help would be very much appreciated.

 

[begreen]

What are the chimney heights on the fpx's?

 

[TulsaOK]

That is the strange thing, on the two smaller fire boxes the shortest one is 15 and it works the best, the tallest is in the bigger firebox and and it is probably at least 25.

 

[begreen]

Are any basement installs? Do they have an outside air supply?

 

[TulsaOK]

No basement installs, all are first floor. One house is conventional insulation, main house is new construction with 4-6" of spray foam insulation. That one is pretty tight. I have tried leaving windows cracked to see if air supply was an issue.mmdidnt seem to make difference.

 

[begreen]

It does seem like a lack of combustion air could be an issue in a tight house. What model FPX is this?

 

[maverick06]

i have an older (2006) FPX extrodinaire (2 door non-cat) the doors are always a mess. Again, the wood is nice and dry (thanks giant covered wood shed). I think the design for the air flow over the glass is just sub-par. never been able to solve it, just something to deal with.