Fireplace blower questions.

[hodag]

Our fireplace has one of the insert style fireboxes that is plumbed to the chimney. It has a fan blower mounted underneath the firebox, but it doesnt seem to put out any air. I took apart the front of the unit to expose the fan, it looks like a squirrell-cage type that is about 18" across and 3" diameter. When I turn the rheostat on the wall it spins like hell, and makes a bunch of noise, but relatively no air movement that I can feel coming from the front.

I cleaned the dust and crap from the blades, shot a little oil on the bearings, and put it all back together. Still no air movement.

Am I wrong in thinking that the fire should heat up the firebox, and the fan should force the warm air out from under there? I cant figure out why it spins like all hell, but pushes no air. It doesnt appear to be in backward or anything.

Any ideas?

 

[Pinion]

Yep. The fan just blows around the hot casing and then out the front. You may have a lot of blockage in there from something, if the fan spins there should be circulation.

 

[freds40]

Does the fan have any kind of shroud to direct the flow or is it an open cage? The open style cages tend to not push much air.

Is the insert gas, wood, pellet,...? Most gas fireplaces I've dealt (Heat N Glo) with produce little heat (in comparison to wood or pellet) and their blowers push slightly more air than no blower at all .

 

[hodag]

Does the fan have any kind of shroud to direct the flow or is it an open cage? The open style cages tend to not push much air.

Is the insert gas, wood, pellet,...? Most gas fireplaces I've dealt (Heat N Glo) with produce little heat (in comparison to wood or pellet) and their blowers push slightly more air than no blower at all .

The insert is just a regular wood fireplace, I have been using mixed hardwood for the fires.

There is no shroud of any kind. I just seems to blow air around the space below the fireplace. The space is roughly 2' wide by 18" deep by 5" high. The fan sits in the middle, slightly closer to the front of the opening.

My guess is that it is just a lousy design that the previous owners paid too much for.

Thanks for the help. Hodag

 

[osagecruiser]

hodag can you post a pic....i have a similar type unit...fan is configured differently and it works great....osagecruiser

 

[haystax]

Where is the air supposed to come from? Is it ducted to the room on the intake side? You can't expect it to pull a vacuum down the chimney and if it was working properly that is what would happen. Not really sure how to retrofit a solution w/o pics.

 

[Pinion]

Picture a shell within the insert.
The shell is the cast iron which gets hot from the fire. The fan draws air from the room at the bottom of the insert, where it travels behind the insert, across the hot cast iron and exits from under the lip at the top.

 

[colofish]

What Pinion said

is right. I have a wood stove insert with a 3 speed blower. The fan is on the bottom and blows hot air out the top. I keep mine on low speed and ususlly only feel enough air flow to move a tissue paper held in front of the top, but it' plenty enough to warm my house.

 

[haystax]

Thanks for the diagram Pinion my reading comprehension was fouled up this morning apparently. I know how useless those squirrel cage fans can be in poorly designed equipment cabs - we've got plenty of those. Probably hard to attach anything that would work and look nice on the front of the unit.

 

[ccondo]

@hodag did you ever solve this issue? My fireplace is the exact design. When I built the house in '98 I paid $150 extra for the blower and it does nothing more than make noise. I had given up on it a long time ago but read this thread and wondered if you'd ever figured it out.

Thanks