Radiant tube heater

[Brad1234]

I am installing a 20', 65,000 btu Radiant Tube Heater. When I layed out the hole to run the exhaust through the wall I realized that I misfigured the location of the roof overhang outside. If I run it the way that I want to I will only have about 2" from the edge of the double wall duct to the vinyl soffit. I don't want to melt my soffit. Does anyone know how hot the side of this double wall duct will get? I'm not concerned with the exhaust opening I plan to extend it beyond the roofs edge.

 

[mobetta]

what is the clearance ratings in the flue manufacturer's literature?

 

[Brad1234]

I have been through the manual many times & I don't see an answer for my specific situation. It does say to use a wall thimble which will create an inch of gap going through the wall which makes me think that I would be okay. I can't turn it to try it because the gas company still has to come & hook up the gas & I'm afraid that they won't if the vent is not installed. I need to find someone that has a radiant tube heater going through the wall that can check & let me know. I don't want to cut the hole until I figure it out.