I have noticed that when the stove runs flat out the coal bed gets too thick (coaltrol MAX 30 and above) and my thermometer over the front door actually goes down from 625F to 500F at say max 38 and the bed does not seem as bright. My coal (Jeddo?) has a lot of fines and that has to play a part in air flow through the bed. Now I have my Gale mining load I see there is much less fines and a slightly bigger rice size so I think that will help a lot. I am also going to spend $90 on a 65 CFM combustion fan vs 60CFM for next winter. I have a powervent unit that I keep at .02 to 0.04 but how about a second Dywer unit over the front door to monitor pressure in the stove and what should it read? LL has a bulletin on the boilers on this issue. House negative pressure is not an issue as this draughty c rappola Victorian leakbox gives plenty of air and I have a make up air vent to the outside. Summer is the time to get it right, of course I am assuming that summer will come soon.
February 2013 The 60 CFM Combustion Fans found on the WL110 and AA220 Boilers have been found to be undersized in some installations, the symptoms are flames coming off the coal bed at full fire that are only 8 to 10" tall. This issue first appeared during the colder weather in January. Research using the 60 CFM fan showed that it needs to be replaced by a 65 CFM fan on some boilers (to ensure no issues we are shipping the larger fan with all new Boilers from now on). The larger combustion fans bolt on in place of the old fans and need to be adjusted for proper over fire draft (the procedure is found here). If you feel you have a under performing Combustion Fan contact your dealer and we can determine if you need a new larger fan.