Vertical Venting For A Pellet Stove

It's very important only to use an approved pellet stove vent pipe in your vertical venting installation. Pellet stoves burn hotter than most other types of stove. Vent pipe is double walled to help keep the outside cool. The walls are separated by an air gap. The inner pipe is made from stainless steel to guard against high temperature corrosion from salts in the exhaust gases. The outer casing is galvanised steel to protect it against rusting.

Pipe joints generally push and twist to lock together. These joints must also be sealed with high temperature silicone to prevent any leaks. A pellet stove vent system is under pressure from the fans that run air into and out of the stove.

Three inch pipe can only be used for runs of less than ten feet. A 45 degree turn will add 20% to the calculated run of the pipe, a 90 degree elbow will add 30%. In general it's better to stay with four inch pipe which will cost little more for a short run anyway.

Pellet stove vent pipe should always run more than three inches away from any combustible materials.
Any horizontal run should have a rise of 1/4 of an inch for every foot.

When installing a vent system, make sure that you will be able to gain access for cleaning.

Regulations For Venting

Local building codes vary for pellet stove vent installations. Check with your local building inspector to find out exactly what's required.

The manufacturer of your pellet stove will also provide detailed instructions for venting, which should come with your stove, or can be obtained with an enquiry.

Vertical Venting Outside

The simplest and cheapest way to install vertical venting for your pellet stove is to run the flue outside, up an external wall of your house. Doing it this way means you don't have to disrupt the house inside or cut through ceilings with the resulting mess that can make.

The pellet stove vent pipe will have to be supported every four feet using a bracket to attach it to the outside wall. If the eaves overhang considerably you will have to run the pipe through the roof at that point, but if the overhang is slight, two 45 degree bends will take the vent pipe clear. Remember to stay at least three inches away from plastic guttering.

If you are venting from the back of the stove, a clean out 'T' must be installed either inside the house if you are running the vent through the ceiling, or outside if you are running the vent externally.

Vertical Venting Inside

If you decide to run your pellet stove vent inside the building, the first thing to do is locate any possible obstructions to the run of the pipe. Locate the joists and rafters in the ceiling and roof around the pipe run you're considering because you really don't want to cut them.

The flue pipe must be kept at least three inches away from combustibles, which applies to joists and rafters. When going through the ceiling, a heat-loss/firestop spacer with a clamp to support the pipe will be needed.

Roof / Cathedral Support Box

In the case of a house that 's open to the roof, or has no ceilings to support the pellet stove pipe, a roof or cathedral support box must be used. This is really just a box which can be cut to the angle of the roof and fitted to it securely. At the base of the box is a clamp to hold and support the pipe.