Harman's website has cleaning procedures for many units & yours may fall under one of them:
(broken link removed to http://www.harmanstoves.com/en/Customer-Care/Cleaning-Instructions.aspx)
I turn the Temp knob to OFF & the feed knob to TEST, once the unit has cooled down to the point where I'm not gonna burn my finners, I start from the top & work towards the bottom. I remove the door, the firebrick(s), & the flame guide & scrapre & brush everything above the burnpot. Then I brush the crap that's accumulated on the side shelves into the ash pan. Dump the ashpan & brush it & set it aside. Remove the igniter cover & clean under the burnpot & with a piece of wire, clear all the air holes. Scrape & brush everything UNDER the burnpot, but be CAREFUL near the fan blades. Vacuum everything up & unplug the unit. Remove a rear shroud & pull the ESP. Clean it with the same stuff you use on the glass. Remove the feeder cover & slide plate & clean that area. Remove the fan shroud & brush the vent from inside the stove into the pellet vent pipe. Clean the fan blades. Brush the remainder of the vent & if inclined, hook up your leaf blower. When you're satisfied that everything is done, replace the ESP, slider plate, feeder mech cover, rear shroud, fan shroud, ignitor cover plate, firebrcks & door. Don't think I missed anything...HTH