Warm Air Duct Temperature

Warm Air Duct Temperature

PostBy: Lightning On: Thu Jan 02, 2014 2:51 pm

During normal temperatures outside thru January and February my warm air off the furnace is around 105-110 degrees. Then like today, its only 12 degrees outside and breezy. I have her turned up some, warm air in the duct is heading towards 115 degrees. During burn off of volatiles with fresh coal, warm air will hold steady around 120 degrees for about half an hour or so. I've also had it goin nuclear when I had some bitty coal burning with 146 degrees thru the warm air ducts.

What is a safe temperature for warm air going thru insulated flex duct? I worry if I were to loose power that the ducts could get too hot since the blowers couldn't run, especially during cold spells when I'm running it hotter than usual. Would they take 200 degrees or more?

Please post your ducted warm air temps... 8-)
Lightning
 
Hand Fed Coal Furnace: Clayton 1537G
Coal Size/Type: Nut/Stove Size Mix

Re: Warm Air Duct Temperature

PostBy: Carbon12 On: Thu Jan 02, 2014 3:07 pm

I think code is something like not above 150. Most plastic flex duct has a manufacturer rating of 200 degrees. Off the top of my head, that is, and that is pointed at times :lol:
Carbon12
 
Stoker Coal Boiler: Keystoker KA-6
Coal Size/Type: Rice/Anthracite
Other Heating: Heat Pump/Forced Hot Air Oil Furnace

Re: Warm Air Duct Temperature

PostBy: Lightning On: Thu Jan 02, 2014 3:12 pm

Carbon12 wrote:I think code is something like not above 150. Most plastic flex duct has a manufacturer rating of 200 degrees. Off the top of my head, that is, and that is pointed at times :lol:


Thanks for the reply :)
What temperature do you think they would fail at?
I'm an outlaw.. Not interested in ratings HAHAHA.. I wanna know what they will take :lol:
Lightning
 
Hand Fed Coal Furnace: Clayton 1537G
Coal Size/Type: Nut/Stove Size Mix


Re: Warm Air Duct Temperature

PostBy: Carbon12 On: Thu Jan 02, 2014 3:25 pm

Somewhere between the plastic deforming and the plastic bursting into flame :D unless the flex duct is coming directly off the furnace plenum,....or very close to it you shouldn't have a problem. If your furnace is burning so hot that the air convection off the plenum is greater than 200 degrees, the flex ducts are the least of your worries! Lol!
Carbon12
 
Stoker Coal Boiler: Keystoker KA-6
Coal Size/Type: Rice/Anthracite
Other Heating: Heat Pump/Forced Hot Air Oil Furnace

Re: Warm Air Duct Temperature

PostBy: Lightning On: Thu Jan 02, 2014 3:33 pm

Carbon12 wrote:Somewhere between the plastic deforming and the plastic bursting into flame :D unless the flex duct is coming directly off the furnace plenum,....or very close to it you shouldn't have a problem. If your furnace is burning so hot that the air convection off the plenum is greater than 200 degrees, the flex ducts are the least of your worries! Lol!


I have it run out several feet with tin from the furnace, then change over to flex duct. I just worry if I loose power, the furnace won't have a steady breeze cooling it from the blowers any more and the air will convect naturally but be much hotter.. I've never shut the blowers down to see, what it would get up to.. :notsure:
Lightning
 
Hand Fed Coal Furnace: Clayton 1537G
Coal Size/Type: Nut/Stove Size Mix

Re: Warm Air Duct Temperature

PostBy: Carbon12 On: Thu Jan 02, 2014 3:39 pm

What are you waiting for,.....DO IT! get back to us with the temperature readings :D
Carbon12
 
Stoker Coal Boiler: Keystoker KA-6
Coal Size/Type: Rice/Anthracite
Other Heating: Heat Pump/Forced Hot Air Oil Furnace