Hello alllong time listener first time caller here. I have a US Stove 6039 that I put a new 6041 board in (originally it had the ABC board) and I'm trying to burn corn in it. The display shows HR1thru10so I tried the holding heat range up/down to switch to corn modeno dicenothing happens. So I tried the tech manual "Adjusting Operational Constants"which it shows C-13 as being the adjustment. It does not go up to C-13stops at C-12. Any ideas on what is wrong or is there a way to set a good corn burn? I've played with manualand auto adjustments and the manual damper only to end up with the pot eventually filling full of corn. The whole back behind the fake brickexhaustand chimney pipe have been thoroughly cleaned. This thing will scream like an F-16 on afterburner with pelletsbut does not like corn.