Harmon Magnum Fan Replacement

Harmon Magnum Fan Replacement

PostBy: dke On: Tue. Jan. 23, 2007 9:51 am

Has anyone replaced the combustion and distribution fans on a Harman Magnum. I am looking for part numbers and suppliers. The original fans are Fasco but the flange dimensions are not the same on the new fans even though they have the same part number.

Re: Harmon Magnum Fan Replacement

PostBy: AL-53 On: Tue. Jan. 23, 2007 6:24 pm

Did you try Graingers...look in the book to try to match up CFM and flange size....also getting from Harman is not bad..they seem to keep the parts sorta cheap...

some fans were Fasco and some were Dayton (maybe)..I forgot the second brand..but there is a thread on the Mag fans here...Harman used 2 brands....

but look at graingers..they have them and may be another brand also...


Re: Harmon Magnum Fan Replacement

PostBy: selveng On: Wed. Jan. 31, 2007 10:51 pm

I tried upgrading the distribution blower last year. I used 2 different fans from Grainger. Both fit with some modifications to the blower flange. I was trying to increase the airflow of the distribution system. Both fans were higher fractional horsepower motors with higher static / cfm fan curves. I ran into nominal cfm increases with blower motor overheating problems. I believe there is too much of a restriction between the walls of the stove to significantly increase the cfm of the system.

Here are the 2 dayton models I tried:
Dayton 4C447 and Dayton 4C445A

If anyone has had better results, please chime in...


Re: Harmon Magnum Fan Replacement

PostBy: BurninCoalInRI On: Sat. Feb. 03, 2007 12:13 am

greg thats a great post! I was wanting to increase the flow myself... I use 4" duct and the air comes out quite hot. wanted more air and don't care if its a little cooler it should still be plenty warm enough.

it never occurred to me that a bigger fan wouldnt work.

BTW how did u notice the larger fans were overheating? How do you know the CFM increase was only 'nominal'?