12/14/12 data, more testing, draft improvementsPosted: December 15, 2012
I added gasket rope which I bought at a local hardware store, which is made to replace the gasket material which comes in a wood stove door between the burn plate and the boiler. This gasket changed the Magnehelic vacuum reading from .1″H2O to .4″H2O. That I thought would make the flame a bit more vigorous. I also made the holes in the bottom of the burner larger to allow the ash to fall through. Lastly I made minor changes by tacking some material across some holes and making more air holes in the ramp plate which the pellets fall down.
The main differences in this graph and the previous day’s graphs are at approximately minute 273 pellets were added and the sawdust which had been running finally ran out. As you can see it had enough energy density to overcome the demands of the circulator circuit. The biggest problem after that came at about 341 when the program allowed the temperature to go past the set point of 140°F The only explanation I could come up with is the division by different types of declared variables was not allowed and yielded a result of zero. I was dividing an unsigned long which is an integer by .8 to increase the Auger Off time by 20%. Since you will not get an integer when you do this the program may not have liked this result. The Arduino language is a slight variant of C++ . I have since made all the variables doubles we’ll see if that works. Today’s burn will be a better test of the burner floors ability to let ash fall through. Sawdust is very difficult to burn. It’s also difficult to get the ash to fall through the burner floor. I think this is because the air cannot get around the sawdust sufficiently to burn it completely and hence it smolders in clumps instead of falling through the grate. The burner when I pulled it out to inspect it was definitely not clean of ash but did appear better than yesterday.