Is there a way to bypass the hi-limit shut off to keep the timer running? I have improved the draft with the setup I have for the DF-520, but still getting out fires since the stoker keeps hitting the high limit. It takes a long time for the temp to reduce below the hi limit, and the fire goes out. I reduced the on-time to 2 minutes per 30 minutes, and removed some insulation to try to get it to dissipate more heat. However, it keeps going out during warmer days without much call for heat. I have the hi limit set to 210 now, but also tried 200. Its been staying lit more with the hi limit set to 210, but rarely can keep it running more than a day or so in the warmer weather.
Try 140 or 150 Low & 200 High with a 10 Diff and set the time for every hour instead of every 30 minutes try 2 Minutes every hr on the timer Your putting in more heat into the boiler every 30 minutes your setting is 4 minutes every hr
cut it in half 2 minutes every hr will put less heat into the boiler so it will keep the high limit from over riding the timer
Also lowering your feed rate and Adjusting the Air will help aswell .