Buckslayer wrote:I agree about not enough air, but there is no adjustment. At an advertised output of 99000 btu this is 19000 btu larger than my old boiler, that never had an issue.
During UL testing we ran the boiler flat out for two days and used an average 65# of coal per boiler operation shift, the output was measured using a flat plate heat exchanger and a flow meter, out put of the boiler was between 85,000 and 101,000 btuh depending on how clean the heat exchanger was. There are lots of variables when trying to get the maximum efficiency out of a unit burning a solid fuel, the first of which is properly adjusting the high fire and idle fire, secondly how often the tubes, economizers, diffuser and combustion areas are cleaned is a large factor, lastly the caloric content of the coal is important, there are coal suppliers out there who mix in less pure anthracite which ultimately affects the output. For the purpose of answering this thread I will address other issues including the one raised regarding combustion air.
At -.14" draft you are too high (the breech is the boiler outlet, so excuse me if I misunderstood your post), although the combustion air issue is a possible cause as well. If you open the small round view port door above the glass and look at the flames, they should be above the diffuser, flickering around the edge and over the top. If not there is an issue with fire size, also how much fuel is burned in one 24 hour period? For the boiler to be at full output with coal valued at 13,000 btu per # you will have to burn around 205 # if the boiler is running flat out and not keeping up. We have had several discussions with customers over the past week with the colder weather stressing their systems. We have found a possible issue with the performance of the 60cfm combustion fan which is related to coal size and static pressure in the plenum under the grate. If the coal is as deep as it should be (up to the sides of the grate) there could be too much blockage with the smaller rice coal sizes.
We are researching a larger combustion fan and working to get them in stock, all customers who have issues with fire size will be offered the larger fan free of charge. Please contact me via PM or call us at the shop at 570-752-1811 if you have concerns related to this thread.
Thank you all for your patience, as always we will not rest until the situation is fully understood and solved.