Slow Whitfield Combustion/exhaust fan?

[MrBeetleman]

I have been having troubles with a smoking stove...(Profile 20)
At startup there isn't the nice strong cloud of smoke coming out of the chimney like there was, and the stove filled the room with smoke.
I just assumed that the stove needed a cleaning.
I have cleaned it like crazy! I was looking at the Combustion/exhaust motor when I am starting it, and it is turning, but slow enough that I can see the cooling fins turning. I eventually speed up, but it isn't turning fast enough to clear the stove of smoke at startup.
Is it a multi speed fan?
Is mine shot, or can I oil it? It seems to turn easily and freely though. I had it off, and used compressed air to clean it...

 

[SmokeyTheBear]

When you cleaned things did you also clean the venting and the path from the heat exchanger to the cavity the combustion fan was in?

Frequently a combustion blower is only idling when in start up.

 

[MrBeetleman]

I did clean those areas, but the area from the heat exchangers to the blower fan is a hidden, hard to reach area. I tried all the tricks I could find on this board.
Thanks

 

[SmokeyTheBear]

I did clean those areas, but the area from the heat exchangers to the blower fan is a hidden, hard to reach area. I tried all the tricks I could find on this board.
Thanks

How about searching on leaf blower trick.

It is where a leaf blower in vacuum mode is hooked up to the venting of a pellet stove and then the rear walls of the stove are thumped to dislodge ash and then the leaf blower is used to suck all of the crap out of the stove.

I prefer to open up and clean all ash traps including any inner ones as well before thumping and using the blower.

 

[MrBeetleman]

I did that....

 

[SmokeyTheBear]

Then get a service manual from Dave Gault, PM member Wood Heat Stoves provide your email address, the make, model, and serial number of your stove. He will likely have a manual he can email to you. That should provide the information to determine if you need a new blower or a new control board.

 

[lmjr]

I have been having troubles with a smoking stove...(Profile 20)
At startup there isn't the nice strong cloud of smoke coming out of the chimney like there was, and the stove filled the room with smoke.
I just assumed that the stove needed a cleaning.
I have cleaned it like crazy! I was looking at the Combustion/exhaust motor when I am starting it, and it is turning, but slow enough that I can see the cooling fins turning. I eventually speed up, but it isn't turning fast enough to clear the stove of smoke at startup.
Is it a multi speed fan?
Is mine shot, or can I oil it? It seems to turn easily and freely though. I had it off, and used compressed air to clean it...

If you're up to it...take voltage readings when it's turning.

Voltage readings are telling you what the control board is putting out.

It is a variable speed output from board...from around low 70's up to high of 115 volts.

Oil the motor if applicable. Trace wiring for loose connections...if you're up to it.

 

[mike_the_elevatorman]

I just experienced the same problem.

I have a Whitfield Advantage II-T. Found a site and got copies of the wiring diagram.

My combustion fan starts up at 120vac, then after about 20 seconds, voltage starts ramping down to 70vac. Not enough exhaust pressure to keep smoke from building up.

Tried jumping / bypassing the switches. Got it to exhibit different symptoms, but the original slow combustion fan still problem.

Any way of bypassing the lower voltage, or rewiring to keep fan on high?

Or, are there diagrams for the control board floating around out there?

 

[arnash]

I just experienced the same problem.

I have a Whitfield Advantage II-T. Found a site and got copies of the wiring diagram.

My combustion fan starts up at 120vac, then after about 20 seconds, voltage starts ramping down to 70vac. Not enough exhaust pressure to keep smoke from building up.

Tried jumping / bypassing the switches. Got it to exhibit different symptoms, but the original slow combustion fan still problem.

Any way of bypassing the lower voltage, or rewiring to keep fan on high?

Or, are there diagrams for the control board floating around out there?

It sounds like the stove might have two problems, 1. the motor bearings/shaft may have been oiled in the past with an oil that thickened/ congealed, and is causing too much friction for the amount of electro-magnetic force that the motor provides to gets the squirrel cage moving at high speed. The blower motors don't have brushes, gears, or belts to make the fan spin, just electro-magnetism, like a mag-lev train. that's why the fans can turn easily in either direction when off. But any resistance will overcome the weak force of the electro-magnetism. So some sort of cleaning of the motor's moving parts may be necessary. If it's a motor meant to be oiled, then that's the place to start. If the motor doesn't make any squealing or whining sound, then the bearings being dry may not be the problem, but rather, they, or the shaft, may be coated with a kind of gunk-y substance causing friction. I hope this can help the both of you.

I can't provide any insight as to why the voltage would ramp down except that perhaps the control board has a way to sense if the motor is suffering from friction drag and so cuts the voltage to spare the motor. Probably someone will chime in with the actual cause. If you clean/lub the motor and it still has the voltage reduction problem, you could hot-wire it directly to an ac outlet with an electrical cord with a plug on the end. Then it would run at full speed and tell you something if it had no problem.

 

[mike_the_elevatorman]

i'll give it a try, using the external 110vac supply. I'll hook up an amp meter and see what the current draw is

 

[mike_the_elevatorman]

well...
fan works fine hooked up to external AC supply, so must be the board
Anyone know where to get board level schematics for this unit?

 

[lmjr]

Hint: Try replacing the triac for that fan output.

 

[mike_the_elevatorman]

noticed one of the heat sinks was quite hot when fired up for just 30 seconds. Was my next attempt. Thought that 220microfarad cap might have been leaky. Swapped that out. Triacs next. Bad part is I can only work on it on the weekends.

thanks for all the help guys!

 

[CJ-SR4ever]

Have seen this problem a few times. For all those times the only thing that worked was replacing the control board. The first time i encountered this I eliminated it being a bad blower, faulty wiring, and snap switches. It is most likely a control board failure, possibly got hit with a power surge or something of that nature. A new board is around $300-$400 depending on the model. Whitfield/Lennox does not support some of the older models anymore so replacement parts can be hard to find. If you can find and fix the issue with your control board instead of buying a new one than that would be the way to go. Best of luck!

 

[arnash]

I'm assuming that my old (1st generation) stove has no control board, though it does have something akin to one, the thing that meters timing of start-up and shut-down. If my stove actually doesn't have an electronic control board, I would bet that some capable person could re-fit a newer stove by making it like an older stove with no control board, thereby saving the cost of an expensive replacement board (which may not even be available). You'd lose the thermostat control and a few automatic sensor features, but hey, manual control isn't rocket science.

 

[mike_the_elevatorman]

another weekend and another flop

replaced both triacs. Still bogs down in 20 seconds. Looks like time to call in the marines...

 

[Snowy Rivers]

Make sure the fan motor is lubed good (remove the little rubber plugs over each bearing and give it a few drops of high temp oil.

The triac is not the only thing in that system. The fuel feed rate controls what the triac is sending to the fan motor.

As the feed rate is increased the fan speed increases some with each higher setting.

You can rewire the exhaust fan and use a remote, manually controled triac (Casa Blanca fan control) and do it that way.

The other option is a fresh board. Dave with wood heat stoves (posts here) can help.

Snowy

 

[PerfectaDude]

Did you ever figure out what the problem was with your blower?