Wow - I am having a tough time. My Harman XXV stove has now gone out or failed to relight 3 times in 3 days. I have written about some of this before, but let me recap. I switched from Energex pellets to Sparkman (Walmart) 11 days ago. 1. Went out Friday after producing lots of clinkers for a couple of days. Stove was running full-tilt. Status light giving 5 blinks (I think). Cause appeared to be that the igniter area was full of ash. I cleaned, and re-lit (took 2 tries though). The top-vent access door showed that the vent is very clear (definitely not clogged). 2. Went out Saturday (yesterday), stove was running high. Status light giving 5 blinks (I think). The burnpot was empty, cause appeared to be pellets bridging over the feed screw. Stirring up the pellets allowed me to re-light and go. This seemed unrelated to failure 1. 3. Last night, the stove had gone out (as it should) when I turned the temp dial down to go to bed. Had been running fine all day. I got up this morning, and found that instead of re-lighting itself during the night as it usually does, it hadn't. Status light giving 6 blinks this time (indicating it shut down for incomplete combustion for 50 minutes). The igniter area was clean, pellets could feed, and the stove re-lit when I turned it off and back on. I can see no reason for this failure. The dealer says it's because I'm not using the pellets they sell (Energex). But the Harman manual says that with its patented feed and burnpot design, it can burn even non-premium pellets. So it's designed to be tolerant of different pellets (might need more cleaning, it says). It says that low-cost pellets can be a cost-effective way to go with the Harman XXV. The dealer may be telling me the truth, or he may be trying to sell me pellets. I am getting a bit desperate. I had a month and a half of terrific operation from this stove, now it keeps shutting down. In desperation, I'm going to go back to the Energex pellets and see if that helps. I want to know if anyone out there is using Sparkman in a Harman XXV ? Thanks for any help you can provide. I may have to call Harman directly if this keeps happening, even with Energex.