QuadraFire convection fan

[B-Mod]

Fan will do the funky slow starts with the stove in low, and med, but never in high.

 

[B-Mod]

On slow fan (not correct) motor connected, the voltage is 80vac, not the 114vac it is suppose to be when running correctly. Both boxes act exactly the same.

 

[SmokeyTheBear]

On slow fan (not correct) motor connected, the voltage is 80vac, not the 114vac it is suppose to be when running correctly. Both boxes act exactly the same.

Was the old combustion unit ever running on the new controller?

 

[B-Mod]

The old fan that died, no. I just put in the other box, when this started to see if the problem would go away with the new box. The both boxes are 2001 vintage, but the one I just installed was only put in for a month when the stove was new. Quadrafire sent me a new box to try that was suppose to give me more heat, and they never asked for the old one back so I kept it, stored away.

Wow I checked the exhaust fan, running with corn burning, on low the fan is turning 400 RPM faster, than it was with no flame, cooled down. Must be the hot air........

 

[SmokeyTheBear]

Ok, that actually answers two questions. The second was going to be about the vintage of the boxes, since you have answered that I'd suggest that you get a replacement triac or two and replace the combustion blower triac on one of the boards with a new one and see how that goes. IF the problem goes away I would then replace the same triac in the other controller and try that.

Maybe they got a bad batch of triacs. This means watch out on the convection side as well.

 

[turbotech]

From your description it doesn't sound like dirty input power is the problem so I would rule that out. I am not sure about the bathroom fan and why the speed is so different. Maybe very different motors. I would try using the exh fan wiring to power the convection fan and see if it does the slow starts on the convention fan during low and med starts. The two are similar in speed and amps.
It is strange that both could have bad triacs. Is that new exh fan a direct replacement as the original?
Did you try tapping the exh motor, control box, and rocker switch area during the slow start? Nothing to hard.

 

[SmokeyTheBear]

...
It is strange that both could have bad triacs. ...

Not if they were buying based upon price in large quantity and got a bad batch.

 

[B-Mod]

I think I am going to order them all and replace them all, better off safe then sorry. I have backup heat. 9 years this thing worked great and now???? Maybe I should just order that Corn Flame stove off of ebay, for $300, lol...........

 

[B-Mod]

I think it is getting worse now that I have been doing this all afternoon. Never thought of wiring the convection motor to the combustion fans power. Tomorrow is another day, as it is took cold to shut the stove down again.
I thought of the bath fan, as a test, but I did not have the little 70 cfm fan, the motors in those are the same type, I only have 110cfm fans, and they use a different type of motor.

Yes the new combustion fan I installed is a OEM quadrafire fan.........

 

[B-Mod]

I read your original post again. It sounds like the extra motor cord is not needed because it runs the exh fan once the power is reset.
It kind of sounds like a failing part in the control box that is sensitive to incoming line voltage. Do you have a power strip that you could power the unit from? I would try that first. I would still check the harness for rubbing / damaged wiring and also the connector terminals.

EDIT: Post if the exh fans stops on medium. I am wondering if the motor current is right on the border of not being enough for the TRIAC holding current when it is on low. Or it could be the optoisolator is not triggering the TRIAC.
You could get the parts as free samples from fairchildsemi.com. They make those flavors of optoisolator and triacs. You can get up to 10 free samples of each so you could replace them all. Are the triacs part number Q6004 and the optoisolators part number MOC 3020?

The opto's are 3020's, the triacs are Q4004F31. All I am coming up with is the triacs are a Obsolete item........ Must have been bad, lol.......

 

[turbotech]

I would see what it does with the conv fan on the comb wiring and go from there. As for the Q4004F31 being obsolete, you can use Q4004L3 in its place. Electrically they are the same. The package is different but where it mounts to the ckt board is the same for the holes and spacing. The F31 has a TO-202 package and the L3 has a TO-220 package. Most designers use the TO-220 package.

For now you can run it full on like you are probably already doing.

 

[B-Mod]

I am an electrician by trade, but not a electronics guy, lol. I will see what it does in the am with the fan switching, I want to thank you, and smokey, for all your help and suggestions. I am living dangerously on the low setting but with a ups hooked to it, so it should keep running, high, gets too hot, and uses a bunch more corn..........

 

[B-Mod]

Tried the test with the convection fan, fan always started but ran near full speed, not a good motor to test with either. I am just going to order the parts. It seems the box I usually run is the worst of the two, now getting to the point I have to try a few times to get the fan to run. Newer box works most of the time. Could still be the fan too but I will try electronics first. I will make sure I post how it goes.........Thanks again............