lsayre wrote:I wonder if leaving the 5/8" hole open all of the time impacts the overall efficiency of these boilers?
Don't wonder measure it.
Years ago forum member Berlin posted a formula for Anthracite Coal,
"high quality anthracite coal empirical formula: C240H90O4NS"
Quoted from his post:
Coal vs Wood Pellets
So what you need is a chemistry experiment. You combine air, (standard atmosphere formula) + burning anthracite and measure the output flue gases. Adjust air as needed.
Measure the flue gases with Bacharach CO2 and O2 FYRITE instruments. That plus gas temperature will let you optimize air inlet for maximum efficiency.
In case you are not familiar with them, here's a description right out of the Bacharach Fyrite owners manual:
The FYRITE employs the well-known “Orsat” method of volumetric analysis involving chemical absorption of a sample gas, such as carbon dioxide or oxygen. The reagent used to absorb carbon dioxide (CO2) is potassium hydroxide (dyed red), and chromous chloride (blue) is the absorbent for oxygen (O2). The unique feature of the FYRITE is that the absorbing fluid is also used as the indicating fluid so that one vessel takes the place of both measuring burette and absorption pipette.
Please post you results here.