fireplace blower blows very little air

[hadman]

Hello everyone,

I have a builders grade Monessen BC36 36" wood burning fireplace. I installed the recommended blower (130 CFM) but I get almost not air out of the top louver. I put a flashlight on the top louver and it appears to be almost all blocked by a piece of metal behind the louver. I was wondering if this was just the design of the fireplace or if there was anything I can do to remove the metal behind the louver so I can increase the air flow. Any other ideas short of getting an insert?

Thanks in advance

 

[Highbeam]

Just about all woodstove blowers make at best a light breath of air as output from their blowers. 130 CFM is quite low. When you get into wood furnace land you will see 1900 cfm blowers. Don't expect much from your fireplace blower. Same with an insert.

 

[begreen]

Stoves/Inserts are area heaters. Folks would complain loudly with a large blower in their insert or fireplace. The BC36 will never be great for heating, it is meant for occasional evening & weekend fires. For real heating with a fireplace you would need to upgrade to an EPA unit designed for continuous operation. Many of these units have a remote blower option that delivers more power while keeping the blower remote to reduce noise in the stove room. Some can also be ducted to deliver warmth to other parts of the house.

Note that installing an insert in this model may not be an option. Check with the dealer. Putting a freestanding stove in front of the fireplace with it venting to a liner in the chimney is a possible option.

 

[Woody Stover]

Don't expect much from your fireplace blower. Same with an insert.

I don't know about other inserts but the variable-speed blower on the Buck 91 moves a lot of air and has four outlets. It's a little loud on high but still moves a good bit of air on low.

 

[Highbeam]

I don't know about other inserts but the variable-speed blower on the Buck 91 moves a lot of air and has four outlets. It's a little loud on high but still moves a good bit of air on low.

Any idea what the CFM is? The ducting can have a pretty big effect on the velocity and the perceived amount of air being blow. Like when you blow out candles on a birthday cake you mostly close your mouth, right?

 

[Woody Stover]

Any idea what the CFM is?

I poked around a bit trying to find that out but didn't have any luck just now. Seems like I found it last year at one point on some obscure motor website. Air moves over the entire top and sides of the stove, it has four~ 1.25 x 4.25" vent holes (would have to measure to say for sure.) Two vents shoot out diagonally, two shoot straight out. The straight-out ones will blow air in your face from 5-6' away. When the stove is cranking, you can't keep your hand in front of the vent for more than a couple seconds.

 

[Highbeam]

I poked around a bit trying to find that out but didn't have any luck just now. Seems like I found it last year at one point on some obscure motor website. Air moves over the entire top and sides of the stove, it has four~ 1.25 x 4.25" vent holes (would have to measure to say for sure.) Two vents shoot out diagonally, two shoot straight out. The straight-out ones will blow air in your face from 5-6' away. When the stove is cranking, you can't keep your hand in front of the vent for more than a couple seconds.

Those sound vastly superior to anything else available today for stoves. I've done some convection deck work and stove blower upgrade work on my NC30 and can also blow hair at 6'. OEM setup, no way. Flipside is that I need to run the stove at higher burn rates to stay clean.

 

[Corey]

True, 130CFM ain't much air, but you'd still feel it. I get a 'detectable' amount of air out of my gasser just from convection...even a small blower would speed that along considerably. The manual doesn't mention anything about removing a metal piece with the install:

http://www.fireplaceblowersonline.com/instructions/FK12-installation-instructions.pdf

Though it also appears the blower may just sit in the bottom of the fireplace (on velcro strips?!?!) and push air in the general direction of the top?

Another manual (I don't think for your specific app, though) mentions some deflectors, shields and brackets on the blower:

(broken link removed to http://c284818.r18.cf1.rackcdn.com/Monessen_BLOT_Blower_Manual.pdf)

Guess I'd take a look at the blower first. Make sure it has all intended baffles, air deflectors, etc and the blower itself is actually putting out a 'breeze' in the expected direction. Next, make sure it's installed correctly and pointing the right way and doesn't have the inlet blocked for any reason. If it still seems like no air, I would explore the metal strip...does it look to be factory, or more of a hack job possibly scabbed in by some overzealous 'installation engineer'? If it is factory and have no obvious 'knock-out' scores or lines, I'd be hesitant to remove it. Though if it looks like somebody bolted it in after the fact, I'd have the sawzall out in a few seconds.

 

[hadman]

Thanks everyone for the replies. I called the manufacturer today and they told me the metal strip is part of the firebox and I cannot remove it. Also, it is normal for 130 CFM to produce only a slight amount of air movement. So, I think as others have mentioned already, this is normal for this fireplace.