Gas Furnace Flue Pipe Sizing

Reduce furnace flue vent connector size below furnace outlet size.

Gas furnace flue pipe sizing.

I have a single 2650 sq ft home that was once subdivided one side had a 133 000 btu oil boiler and i have a 115 000 gas boiler. When we are talking about gas furnace vent pipe code we need to talk about the different types of the vents first after all you want to keep your family safe from harm. The size would depend on your furnace s flue pipe connection. Traditional gas fired forced air furnaces produce hot combustion exhaust gasses and therefore need metal vent pipes or chimneys.

So let s calculate or why don t we skip those calculations and i ll give you the answers. The pipe then slips into the hole and is sealed with a high temperature silicone caulk. Conditions for listing as stated in the product catalogs and embossed on the vent pipe. Oct 13 2012 brent said.

You would core a hole 1 4 to 1 2 inch bigger than the outer diameter of the pipe. The different types of venting. Clearance installations must provide the proper clearances to combustible materials as specified in the appropriate underwriters laboratories inc. To make it simple if you have a gas water heater with a 3 draft hood and a furnace with a 4 flue collar connected to the same chimney flue you d calculate that chimney flue size based on the 3 draft hood the smaller of two.

In contrast modern high efficiency condensing furnaces exhaust much cooler gasses and need only plastic pipe materials such as pvc cpvc or abs for their exhaust vents some high efficiency furnaces also include a plastic pipe for intake area and all types.