Question about venting garage furnace

[Steven J Corpstein]

I just installed a furnace in the garage/shop and the guys that put it in said go with a 3' vertical vent through the roof, but the manual says 5'.

The problem with a 5' flue is that I have a hip roof with a low pitch, so a 5' flue sticks up above the roof about 4', catching wind and really getting moved around. I really don't want to brace it to the roof, looks terrible.

How many of you have used a 3' flue and do not get condensation problems because of the length, etc.? The horizontal pipe is only about 2' long on the inside of the garage.

[Matt Meiser]

Assuming you are talking about one of the Hot Dawg heaters, why not vent out the side wall?

I would follow the manufacturer's instructions.

[Jim DeMarco]

Steven,

Do not quote me but I believe as long as the flue is higher than the peak you should be ok.

[Mark Rios]

The code for the top of a heating vent or flue like you mention is: 2 feet above the nearest point within 10 feet. In other words, whatever the highest point is within a ten foot circle, the top of the vent has to be two feet higher than that. Has to do with it venting properly.