Time to clean the black carbon build up on the exhaust impeller blades

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Don2222

Minister of Fire
Hearth Supporter
Feb 1, 2010
9,186
Salem NH
Hello
It takes a bit of scrubbing with the wire wheel on the drill driver but I think that black carbon adds some wind resistance when turning. Cleaning and spraying with some dry moly makes the petals smooth as silk and reduces that resistance quite a bit. Also clean any dust from motor.
Object of this cleaning:
- Increased surface smoothness
- Corrosion Protection
- Decrease adherence of ash and other contaminants
- Decrease drag and increase effenciency
- Prolong motor life
It is also possible to replace the impeller blade with a new one if it is too rusted, pitted or broken. :-)
 

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Such an overlooked preventative maintanance task....thanks for posting this! I’ve also had really good results using a heavy degreaser and spraying the fan blades, put a cloth underneath to keep the mess down, the degreaser breaks the carbon down and helps ease the cleaning.
 
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My fan comes off the shaft easily so I just put it in
the sonic cleaner after about an hour looks like new
 
The best way I found to clean my Harman pellet stove combustion blower double paddle impeller blade using white aluminum oxide and a Trinity Trinco industrial blasting cabinet I picked up used for $150 and rebuilt. :) It really gets that stubborn ash of the sides of the petals with just a little more blasting!!!
 

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I usually clean my exhaust fan about every six weeks when I'm burning hardwood pellets at the height of the heating season. I never find any deposits on the blades that I can't take off with an old toothbrush. The deposit on the backing plate is a little denser but scrapes off easily with a putty knife.

If I don't keep the exhaust fan clean, I start to get misfires and half-burned pellets dropping into the ash pan, where they smolder and let smoke into the house.
 
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All I ever got was dust on my Harmon XXV. I just use paintbrush and brush it off. Vac to suck up the dust. Hard part is getting down low for me. I only burn softwood pellets (all there is in WA State)
 
I found soaking it in the degreaser easy too, I’d love to have a sand blast cabinet, just not enough room. Here’s a couple pics of the impeller after the soak. I’ve been 3 for 3 on getting them off of the shaft too, PB Blaster is priceless!
 

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All I ever got was dust on my Harmon XXV. I just use paintbrush and brush it off. Vac to suck up the dust. Hard part is getting down low for me. I only burn softwood pellets (all there is in WA State)

Same here, just a layer of ash on mine and it comes off with a stiff brush, only because it’s so compacted. Black deposits would make me think I’m not getting enough air. But everybody’s stove is different.
 
I agree, Black Deposits sign of not enough Air. Only time I ever got black in my Harmon is when I left Metal Fabric I use in the Chimmney to keep Birds from coming in. Removing that solved it. I also put magnet on the flapper for OAK and that would solve it. But the real fix was proper flow thru chimney. Amazon product ASIN B01N5KT4BE
 
Also good to scrape off any dirty ash behind the impeller blades?
 

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Cannot forget to cleanout any ash in the exhaust blower housing too at least once per year!

1st Pic shows 3 years worth!
 

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