Phil Stevens wrote:I can't say for certain without seeing a burn (and listening) in person, but my hunch is that you might not have enough turbulence in the burn chamber to mix all the exhaust gases with incoming air for complete combustion. Your firebox is basically a box, right? In the photo it looks like a big L-tube and although it's a very free-flowing design, it doesn't create a venturi in the same way a J-tube would, nor does it have the secondary air channel of Peter's batch box design. So, even though you're getting sufficient temperature, it's not getting the mixing effect.
Gerry Parent wrote:Is that a casserole dish lid? If so, it does look nice but do be warned that quite a few people that have used them have commented that they either crack or shatter under the intense heat/cooling they experience. Casserole door In particular, Matt Walkers comment about a 1/4 of the way down.
Phil Stevens wrote:Have a close look at the evolved and tested design of Peter van den Berg's batch box. The secondary air channel and port are critical to success in this breed of RMH. Just putting in a restriction may give you even more draft issues.