All the Piazzetta stoves are set up that they can be calibrated with a magnahelic gauge- If you have already made changes to the stoves settings, I assume you have the codes to access the menu parameters screen. There is a brass acorn nut threaded onto a port on the back of your stove above the power cord, this is where you would attach the tubing on your mag. There are factory recommended vacuum readings for each power level, you would adjust your smoke fan rpms to meet those benchmarks. In my experience, if you are burning hardwood pellets, I have found calibrating the vacuum for approx. .02- .03" W.C. above factory recommendation helps prevent build up in the firepot. I just attended the HPBA expo in Salt Lake city and I saw an updated firepot Piazzetta is offering for the larger units (Sabrina, Sveva, P96 series). Its has a stainless steel deflector bolted to the back of the firepot underneath the auger tube, apparently to increase the venture effect in the firepot and help eject the ash. The target vacuum settings for the Sabrina are as follows- power 1 (18P) .24" W.C., power 2 (19P) .26" W.C., power 3 (20P) .30"W.C., power 4 (21P) .34" W.C., power 5 (22P) .38" W.C. Again, this is the factory recommendation, these stoves are operated almost exclusively with softwood pellets in Europe so results will vary when dealing with hardwoods.