FPX Apex 42 burning questions

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New Member
Jan 26, 2024
Arcadia, OK
glad I found this. I have a FireplaceX 42Apex (which is a "fireplace" but basically a wood stove in a box with a blower) and have been learning how to use it through my first winter. It's a shame how the operating manuals on these things seem to be written with experienced wood stove operators as the expected audience. I've been afraid to turn my air control down below about 40% because if I go all the way down, or even below about 25%, the flames disappear entirely and I thought I was smothering the fire and coating my flue with extra creosote. As such, I go down to where I maintain flames and I can still let it go 8-9 hours and have enough coals to reload without starting over, but I don't want to leave heat on the table and burn through wood faster than I need to.

I do have a fairly tall chimney, it's all relative but probably just under 30', but with air control fully open it burns at about the same intensity as it does with the fireplace door wide open but maybe a hint of that slow-motion flame effect, so I figure it's getting enough, but maybe I just need to find the right point in the air control.

I'm also learning how to make sure my wood is dry...started out just checking the ends but then i started probing the middle of the split face and realized some of the wood that was measuring <10% was really 15%+. The stuff I've measured between 15-20 doesn't seem to burn as readily as the <10 stuff, but I'll start checking the fresh side right after I split it and maybe I'll learn that what I've been measuring at 18 might actually be higher than that.
The position of the air control is relative to many factors like the chimney location, offsets in the flue, the species and thickness of the wood splits, the moisture content of the wood, firebox loading, etc. I'm not sure what is the case here, some inexpensive moisture meters aren't very accurate. However, if the fire is burning well and the chimney is staying pretty clean, then running at 40% air may not be a bad thing.

Based on the description, the likely suspect is the wood.. What is the air control setting with the drier wood/
My friend has this stove. Im not sure if its the 42 apex but I know its a fireplace x. Hes in a 2 story colonial so Id say the chimney height is similar. His stove is pretty easy breathing. If your stove is like his, it has a built-in cat probe. When your closing the by pass you should see your catalyst temperatures rise.. you should be able to see the catalyst glow also if you look up unto the box. Regardless of weather or not the flames go out or not if your catalyst is getting above 500 degrees your catalyst is starting to work and should go well above 1000 degrees

Your wood may be borderline at best.. Id definitely check the quality of the wood because it will cause some performance issues and create the creosote issues your trying to avoid