# furnace problem, solved just curious why.



## kendallt (Feb 21, 2007)

Last year I heated my trailer with my old Vogalzang boxwood stove, and my shed/hideout with electric heat. This fall I decided to hook up my old pole barn wood furnace to heat both. 
Furnace is rated for 2000+ square feet. Pulled out the fully functional propane furnace because it's cheaper to run electric space heaters in every room than to use propane here. Connected wood furnace to the trailer duct work,using 10 inch insulated flex duct. Also Installed a T in the 10 inch flex with a reducer to run 6 inch into my hideout which is 15ft from trailer. 
The ducts in the house are 3x15 flat ducts, and I used the same central feed as the old propane furnace did to pipe in the hot air, this gave me two 3x15 ducts, one each direction. 
Problem is that I could not get air to flow well enough through the ducts to heat the trailer. Even changing through all four speed settings on the blower. 
The air that came through was plenty hot at 120+ degrees, but simply wouldn't flow enough to warm the house up. My math shows that the flat ducts have more area than the round duct so shouldn't choke the airflow. (3x15=45, x 2=90 square inches), Against the ten inch duct's 78 square inches (5x5xpi) So it should flow freely, but it wouldn't.
Ducts are clean and clear, it worked fine with the original furnace, and I stuck my camera on a length of PVC pipe, and fed it from vent to vent and no blockage was visible. Also installed the propane furnace blower on my wood furnace, with the same results. 

Solved it by picking up more insulated flex duct, and feeding each end of the house with heat, and plumbing the return to the center of the house, works, 30 degrees out and had to open windows. My hideout stays the same temp as the house as well, which is the important stuff!

Anyone have an idea why it wouldn't work when installed 'correctly'?


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## charlie1776 (Jan 19, 2011)

Usually, mobile home furnaces come with a high static blower. This is to move the proper amount of air through the ducts being that they use much smaller ducts that save on weight and space. Normal blowers can't push the air though the smaller ducts and turning the fan on high isn't going to do the job. The difference is in the squirrel cage.


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## kendallt (Feb 21, 2007)

That explains it then!
had been racking my brain because everything I measured said it should have worked fine.

Thanks!


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## charlie1776 (Jan 19, 2011)

You're welcomed!


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