Yes I have, this was a full clean. I always clean behind the small doors.

Haven't done circuit board switch yet cause not here. I did full clean of unit using leaf vac on outside of exhaust tube. Pulled baffle off and noticed tons of ash hoping this could be part of the issue. I've done everything other than circuit board so it has to be it. U1 is 315 and u2 is 88. I'm stumped.


Baffle is back on, I have never removed it. Pulled off to clean and reinstalled

Reset codes, no difference. Tried another vacuum pressure switch, no difference

Gonna try this. Think and know there is soot on baffle yhat I cant get. Goin to remove to clean and do a leaf vac outside on exhaust tube. I think the soot ontop of baffle is insulating and not letting exchanger do its job and heat goin out exhaust.

Yes flue is clean, I run a 3" chimneys brush through it and thats right at the exhaust fan into the t and then from the t up and out to exit. I can get a new circuit board for $219. The draft fan light goes on right as the exhaust fan quits. The furnace will stay on but exhaust fan is off until something cools enough for it to regain conscious. There r no obstructions from what I can see. What about the heat exchanger not working properly? From what I put in my last post, is there a way that if not working properly the heat will escapes through glue. Tell me what u think

I am coming to this conclusion. I noticed that the U1 reading did go below 160 when off and cooling. I think something is going on (that I havent figured out yet) where the exhaust is getting more hot air than it should. I am running on manual draft with dampner out 1". I have tried on auto and noticed no difference. Would there be something inside the fire area that would allow the heat to exit through the exhaust? Would it be the heat exchanger not exchanging the heat properly? How do u know if it is or isnt working? I am running c-2 at 3.8lb/hr and c-3 at 8lb/hr. I have had these at c-2 7lbs/hr and c-3 at 14.24lb/hr and never had an issue with the U1 reading going so high that it shut down the exhaust fan. Any clues or advice please post.

I have and do annually if not semi annually. I pull the exhaust fan out and clean paddle of soot with a toothbrush . I clean soot with a 4.5 HP stanely vac. Cleaning fire burn area and whole exhaust area.

I have it using a 3" Simpson double wall exhaust. Runs 4' feet up on a diagonal and does a 90 degree shooting out of house with a 3' run. Have used this exhaust system since we had it, all 4seasons. The exhaust thermitor is the factory thermistor. All the parts I have switch have all been from ussc. We figured it was a dirty thermistor causing issue, cleaned and reinstalled, no difference, exhaust fan just stopped. Called ussc and they sent me a new exhaust thermistor, no difference, u1 approaches 550 and just shuts unit down

For some reason the u1 reading is higher than it should be and no one at ussc could answer me on this. It's 160(u1) when the system is cold and has not been run . I just don't want to buy a new circuit board and have same problem with exhaust fan shutting down. Don't want to have this turn into a nickel and dime issue. Thanks for the help.

The first 2.5 season I have been able to run 110-115 degree heat with no issue, not sure of u1 reading. Now I cant go over 75 degree actual warm air cause it will shut exhaust fan down due to u1 reading climbing towards 550. Like I said before, Paul Williams from ussc claims exhaust temps should be reading no higher than upper 300 and u2 readings should be 130-140. I get u1 at 550 and u2 at 128

I have a american harvest 6500 goin on its 4th season. Had this issue last year but was able to make it through bein it was a mild winter. The unit worked great and could push any temp heat the first 2 seasons. Here is what is goin on and I am curious if anyone has dealt with these issues.

I will have the furnace running and working great, i notice its holding the same temp in the house or has dropped a degree so I turn it up to cr-3 heat setting. c-2 setting is 4.5lbs/hr c-3 setting is 9lbs/hr. The factory setting happen to be c-2 is 5lbs/hr and c-3 is 13lbs/hr. I've had to drop the feed settings to be able to use the pellet furnace.

I will watch the U1 reading which will climb so fast (U1 tells ur exhaust flue gas temp) while the U2 reading barely raises (U2 tells u the duct temp). I happen to have a meat thermometer probe stuck down where rectangle duct goes on which I can only get it up to 75-80 degree heat and the U1 is around 550-560. I have gone to the adjustment settings and have raised the exhaust temps to 670 but no difference. When the U1 reading hits 550-560 (U2 is reading 125), the exhaust fan will just stop. this means pulling no air over fire to feed it. Draft fan light is on solid. I have switched out with another exhaust fan which i have as a spare, same thing, the U1 reading hits 545 and it stops exhaust fan.

When the stove is off and cold, the U1 reads 160. I have been told by paul williams (USSC) that the U1 should be no higher that the 300-400. I have consulted USSC and Brandon (one of the engineers) claims the computer circuit board needs to be replaced. tell me what u think and if u have dealt with this what have u tried. the exhaust and duct thermistor are both new and the vacuum pressue switch is new with 2 spares. I have have tried everything i know of.

I have thought that as well, thanks. I guess I have to run a higher percentage of pellets to corn in futurt or ratios will have to be very close

so, I am burning corn and pellets (7:1 corn to pellets), the pellets to help reduce clinkers in my ussc american harvest 6500. The problem is that I am still gettin clinkers sticking to the firepot not allowing ash to fall through the holes. I am running on cr-3 (high setting) my fuel feed around 9-9.5lbs/hr pulling around 95-100degree heat. what are u guys doin that i am not to rid of these clinkers that are allowing my fire pot to overfill and I have to be constantly checking on. Also, who here has a USSC 6500 and what are u runnin it at? Low end fuel (C-2) high end fuel (C-3) heat level, draft setting (auto, manual, semiauto)(I know this will be different cause every where is different wind streams). I love burning corn over pellets but I dont like clinkers. Last year I burned 7 tons of pennington pellets and mix 40 bushels corn w/ that, had no clinkers or any issues. Now I have 280 bushels of same corn w/ 3 tons of same pennington pellets and having clinker galore. I want to go to bed at night not having to worry about firepot becoming to full and not putting heat like it should if clinkers weren't an issue. I live just northwest of Grand Rapids, MI, thanks, John