Harman 52i insert running low all of a sudden

Stove's been installed and running just fine for 5 years (minus what seems to be a yearly replacement of the combustion fan motor). No issues at all this season so far. Running doug fir pellets as always, and last full cleaning (without pulling the insert out) was in November, maybe half a ton through the stove since then. Last time I pulled the insert out to clean the pipe was the end of last season. Put maybe 2-ish tons through it this season so far.

Yesterday morning, pellets just about ran out of the hopper and the stove was essentially shutting down. Tossed a bag in from my basement and it came back to life just as expected. Later in the day, hopper was maybe 1/2 full, so added some more. This time from a different brand of doug firs, from a pallet I just opened (was in the process of transferring bags to the basement).

After an hour or so, the stove seemed to be shutting itself down even though the hopper had plenty of pellets. There were some pellets in the hopper lid seal, so I thought maybe it never sealed correctly when I added. So I cleaned it out. I manually tossed some pellets in the firebox and things seemed to come back to life....thought it was all good...and I left the house for a few hours. Came back and the stove was off. I run the stove in manual mode, so it shouldn't shut itself off.

I fired the stove back up manually using starter gel. It fired up and seemed to be running fine for a small period of time. Now the stove is running extremely low, i'd guess like half power at the moment. It's not in maintenance burn mode like the RSP is satisfied, it's simply like the stove won't get to full power. I have the thermostat cranked all the way up. I had to turn the feed rate up to 4 when I usually can run it at 2 with doug firs. If I turn it to Stove Temp Mode, the distribution fan shuts off even though the thermostat is still cranked all the way up. If I go back to Room Temp Mode, the distribution fan comes back on.

I have no status light blinks at all. My next move was to burn the rest of the pellets out of the hopper then take it out and check the exhaust port and ESP. Combustion motor sounds just fine. Could I have a bad ESP or it's covered in ash thinks it's running hotter than it really is somehow?

Any ideas?

Thanks! The firebox flame does visibly change when I open/close the hopper. Any advice on how to check those other things? The wires I can easily check, but I highly doubt since it was changed out of the blue....unless a mouse chewed them or something.

What about the fact that the distribution fan stops as soon as I put it in stove temp mode?

Ok, maybe I need to understand stove mode better...

Now, would any of those other problems also through a status blinking code? Because I don't have anything blinking.

Update: After reading that thread, seems like the exhaust is cold enough to not turn on the dist fan, which makes sense. Putting it in auto now, the dist fan comes on as expected. I still have thermostat cranked and we'll see if the stove kicks up at all with it in auto, stove mode H, and level 7 on the t-stat.

Well I think I found my problem LOL! The last bag I put in was from the bottom of the pallet....and the bag was torn. Looks like a piece of cardboard made its way into the bag, I didn't notice when I poured in the pellets, and was now blocking the feed screw a good 60% of the way.

Also, especially with Doug Firs, I never find the need to clean the chimney except every spring when shutting it down for the season.