Mt Vernon heat selection knob not working

Hello, everyone.

I have been searching the forums for a while now and cant seem to find an answer to my problem. One thread started down the road only to eventually end up with a dead end. I have an older Mt Vernon stove that has recently acquired some problems. I just replaced the convection and combustion motors due to squeaky bearings and now I have a new problem I cant seem to figure out. When the stove is started I can use the heat adjustment knob to change the output at start up. I can hear the different tones in the exhaust fan when turning it from low to quad. However when the stove is at temp and the convection blower turns on it seems to not matter what the knob is turned to the fan blows at a constant speed, most likely low or medium if i compare it to previous runs. It doesn't really blow much heat. I did check the fan to see if maybe it had gone bad but it blew on quad/high when plugged directly into a wall socket. So i know its not the issue. Could there be a wiring issue here with this fan. It had worked before however the new fan came with an extra wire. I connected the white and black ones to respected terminals and left the red one grounded to the stove.

Thanks

Lake Girl said:

Troubleshooting guide: http://www.mortonsstoves.com/wp-content/uploads/Quadra-Fire-Mt-Vernon-Troubleshooting-Manual.pdf

Have you checked thermocouple connections and to see if it is delivering proper voltage?

Apparently the heat selection knob can be replaced but you mentioned you didn't figure that was the problem
http://www.pellet-stove-parts-4less.com/product_p/7000-128.htm $69

Click to expand...

I have not checked the thermocouple. I'm waiting on a multimeter. It seems like it's running normal without the ablity to change the stoves rate. Starts up and runs as well as shuts down. It does seem to be running at a constant low/medium setting. Based on flame height and how many much pellets are being burnt. Almost inconsistent. I'm leaning toward the controll box but I need a way to rule everything out

Well The fan size and dimensions were exactly the same so i figured it wouldn't matter. Figured the red wire was the ground. Baught it from pelletstovepro.net. Hoping the barrow a multimeter this weekend.

Last night when I returned from work, I cleaned the pot and put restarted the stove. I found that when messing with the selector knob that exhaust fan speed was faster with the low and medium settings. When i clicked it to high or quad, the fan speed dropped and no noticeable difference between the two. I left it on medium throughout the night. This morning I came down and turned the knob to high for kicks. Sure enough it came on and the convection blower sounded healthy.