2008 quadrafire Mt Vernon AE convection fan issue.

[robinsonzak]

Hi All,
I have a convection fan blower issue on my 2008 Mt Vernon. The stove ran all last winter (purchased used last fall) and sat all summer, I fired it up three weeks ago and it was running fine until one night it smelled a little warm and then I got a drop tube max temp error. I reset the stove a few times before realizing that the convection fan was not turning on to push the heat out, and the drop tube was heating up because of that. I removed the fan, rigged up a flexible duct to a small external fan, dropped flame height to -5 and found that the stove would run fine in that configuration so I could troubleshoot the fan and system. I removed ring TC on drop tube, sanded mating surfaces, tested TC with a millivolt meter and a lighter and I was able to observe a rise in millivolts with heat but didn’t get any great consistent readings (its a low quality meter with a millivolt setting).

I removed the overheat snap disc and cleaned mating surfaces, and checked it over a flame with an ohmmeter and it has continuity, but I also found that even once it snapped it still had continuity.

I removed the control board to inspect/clean and in the process broke a pin off TC1 for firepot TC and had to solder in a new pin.

I cleaned out the fan, tested the wiring harness from end to end, took apart the fan and plugged the harness in and tested continuity from end of harness to solder points on fan motor.

I purchased a new fan and plugged it in, got the stove up to temp with flame height at -3, used an infrared thermometer to make sure drop tube temp was well above 105 degrees and still nothing. With drop tube temp well above 105 degrees I removed the fan wiring harness from the control board and got very low voltage numbers. I’ll attach video below of what I got for voltage readings. I also retested the drop tube thermocouple tonight with the stove heated up rather than using a lighter and couldn’t get a decent reading at all, I plan to pick up another meter tomorrow to double check.

I’m at the end of my knowledge here, could it be as simple as a Drop Tube TC that’s not getting the right millivoltage? Wouldn’t the unit not run at all with a bad drop tube TC?

Thanks in advance,
Zak

 

[robinsonzak]

Here’s a link with photos of the unit, and a video of testing the voltages at the fan-end of the wiring harness with the other 2 ends plugged in to the board (stove is up to temp and infrared thermometer reads over 105 degrees at drop chute.

iCloud Photo Sharing

iCloud Photo Sharing lets you share just the photos you want with just the people you choose.

www.icloud.com

 

[ChilepinesNH]

I have essentially the same problem. My stove goes to Startup, SS-Low, SS-Med, then runs on Manual MH for a while before I get a Max Drop Tube Temp error. All through this the convection blower does not turn on.
I checked the snap disc and it seems fine - has continuity when set, and I can get it to trip and reset. To be sure that was not the problem I jumped it and it made no difference.
It does not seem to be the Drop Tube TC that is the problem - I heated it with a heat gun and was able to get voltage, and it must be getting voltage since it is sensing the high temp.
How do I test the convection blower itself? I read in another thread where someone suggested connecting to 120V AC, but it sounds like everything in this stove is 12V DC.
This stove is now in a wood shop in my barn so I'm not reliant on it, but I'd love to solve this!

 

[rickwai]

Sounds like you have a bad fan motor. They run on 12V. not easy to troubleshoot. The ones I have worked on that fan was not working I replaced the fan and reset the hi limit and all went well. The insert model is a pain to replace the fan. very close quarters.

 

[ChilepinesNH]

Thanks for the info rickwai! I have the fan motor out - any idea which wires I get 12V to see if the motor runs? I'm guessing the red and black but would be nice to know before I try it.
Also, what is the hi limit reset you mentioned?

 

[robinsonzak]

I replaced the fan motor, no luck. I then replaced the board and it’s worked great since then. Where are you located ChilePines? I have a brand new spare fan motor here now and you’re welcome to use it to test your unit, If it works I’d be happy to sell it. I’m in Eliot, ME.

 

[rickwai]

The reset is on the underside of the drop tube. Kap should see this and should be able to guide you on testing the motor.

 

[Heathnortheast]

I replaced the fan motor, no luck. I then replaced the board and it’s worked great since then. Where are you located ChilePines? I have a brand new spare fan motor here now and you’re welcome to use it to test your unit, If it works I’d be happy to sell it. I’m in Eliot, ME.

I need one in Naples maine

 

[Heathnortheast]

I have the same unit and have been battling issue after issue after years of none. My thermostat went and it ended up being the power inverter and some bad connections that were smoked. I replaced the power inverter and connections and it threw a few codes like comb blower, drop tube and something else so after tons of head scratching and being cold I just got the new control board and it changes nothing and I’m about broke well I am broke!! The same people telling me to throw parts at it told me to get new board so idk what to do please help me!!

 

[ChilepinesNH]

Reviving this thread as it is getting cold out in my shop. I have the convection fan out of my stove and am trying to determine if the fan is the problem. There is an 8-pin connector from the stove to the fan - red-black and the two sets of white-blue-green wires. Putting 12V to the red-black pins does nothing. Putting 12V to one of the white-blue-green sets (any combination) causes the motor to jump, but not continue running. I do see good current flow across those pins without the motor turning.
Does anyone know whether the motor should actually run when given voltage? Does this show that my fan motor is shot?

 

[Jazz_nh]

Help. Reviving this thread was I am having a similar issue. I have a Quad. Mt Vernon AE.
One morning the stove had an error on it, and it was for one of the blowers being jammed. I did not take note if it was the Comb blower or the Conv. blower before I cleared the error.
Upon reset, I keep getting Max Drop tube temp.
I have fully cleaned the Combustion Bower, as well as the Convection Blower as well as the entire stove. .
Same max drop tube temp.
I replaced the Convection Blower. Still nothing.
I just put in a new Snapdisc as well as a new TC... NOTHING. The stove does its start up fine. Fire starts, combustion blower spins. Auger feeds pellets.. all perfectly fine. After about 10 mins, the stove errors out for Max drop tube temp. Brand New Convection Blower. Brand new Snap Disc and Brand new TC on the drop tube. The Conv Blower never starts. What am I missing ??