[michael cook]

I was given a lennox propane furnace today for my garage they had it in the basement and used single wall galv venting I need to no if I need to run double wall and can I go straight up thru the roof ceiling is osb along with the roof sheeting any advice appreciated thanks also should I run a trunk line with off shoots or just 1 big vent off of furnace garage is 24x32 but might add another 24x20 in a year or 2 thanks

[dinger]

Get the model number and find out the clearances and type of venting that need to be done. Single wall as in bvent for the old installation? A roof flashing will be needed, you should be able to penetrate obs as long as the proper clearances to combustibles are maintained. Dan

[robs ss]

I have a reznor 65,ooo btu, in the overhead, I doubled up the pipe going through the roof, wether I needed to or not, my garage is 24x 24 with a 26x 30 added on the back, so its 1356 sq ft, I just let it blow right out the end, no duct work, I have used it since 1990, and never had to touch it, knock on wood huh.

I can take it up to 78 degrees, thats as hot as I ever went with it, might be more left, but it will heat, its natural gas.

Rob

http://www.1969supersport.com/

Oh, I went through 7/16 aspenite, six inches of insulation, 7/16 aspenite shingles and out.

[59 wagon man]

if you are passing thru any combustable material you should def use double wall or b-vent pipe . you will also need to maintain minimum clearances with b-vent usually an inch or so to combustables