Quadrafire 1200 early shutdown

[freshj]

Hello! I was hoping somebody could help me troubleshoot my Quadrafire CB-1200-I. It is 15 years old. Last year, I began having nuisance shutdowns for no apparent reason, but I could usually get it to restart and stay on with the manual reset. This no longer works. I replaced the thermocouple a few years back, when I could no longer run it on low speed, but it would work fine on medium/high settings.

Yesterday I replaced the control box (initially set on '1', now have it switched to the '2' setting) thinking this was the culprit. It goes through all the normal startup and operation for approximately 15-20 minutes. Thermostat call light red, exhaust blower on, igniter, auger for 60s, pellets ignite, green LED, feed motor cycles, red LED, convection blower for a few minutes -- then red LED turns green and feed motor stops, convection blower off, I hear the exhaust blower start cooldown, and units burns out. I'm pulling my hair out at this point...because our heat pump quit recently too, and lead times are crazy to replace it (and electric only furnace heat is expensive ).

Any help is appreciated. I haven't replaced any of the snap discs yet, or checked the vacuum switch (which has likely never been cleaned). I checked and cleaned the exhaust yesterday when I pulled the unit out to install the new control box. It's almost like the unit is thinking the thermostat reaches temperature, and turning off prematurely, but I have no clue. I also haven't removed the pellets in the hopper to check the auger, but it seems to be dropping pellets normally.

Thanks!

 

[freshj]

Update - it does seem to work on the high setting. Stayed on for an hour before I shut it off cause it was so hot . Hope that helps narrow it down.

 

[tnt4him]

Update - it does seem to work on the high setting. Stayed on for an hour before I shut it off cause it was so hot . Hope that helps narrow it down.

I'm not sure what it is, experiencing some of the same issues on a 2006 santa fe. For starters i plan a thorough cleaning and specifically on electrical connections. Temperature seems the common fault.

 

[freshj]

Well - I think I found the problem. The auger feed gate was the ultimate problem. I also did a thorough cleaning of the exhaust chamber, and really the whole unit. But essentially, it wasn’t feeding enough pellets per drop to keep it hot enough which sent it into shutdown sequence. Problem solved for now!

After doing this it works on all three speeds just fine.

 

[tnt4him]

Great job figuring it out! Reminds me of a similar problem i had when the pellets were few and it kept shutting off prematurely. It was temperature probe on the fire pot. It was black from soot and ash and full of ash particles. I include it now on my weekly cleaning.

 

[You'refired]

Well - I think I found the problem. The auger feed gate was the ultimate problem. I also did a thorough cleaning of the exhaust chamber, and really the whole unit. But essentially, it wasn’t feeding enough pellets per drop to keep it hot enough which sent it into shutdown sequence. Problem solved for now!

After doing this it works on all three speeds just fine.

Could you explain what the problem was with the feed gate? If it worked before I am just trying to understand why now it wasn't feeding enough pellets. I am having a similar issue!