Pellet stove flue outlet: what to check before you order

Why the flue outlet decides which version to order

On several ranges (Edilkamin Cover and Rise, some of the Girolami models), the flue outlet is a variant axis: rear, top, sometimes side. The manufacturer code and the price change with the outlet. Checking the outlet before you order avoids an appliance turning up with the wrong flue spigot.

Diameter: 80 mm in most cases

Most pellet stoves have an 80 mm flue spigot. High-output hydro stoves and some models above 12 kW go to 100 mm. The diameter is given on the technical sheet ("flue outlet" field). The connecting flue pipe keeps this diameter up to the vertical flue; you never reduce it.

Connecting to an existing chimney

An old masonry chimney is lined in stainless steel, rigid or twin-wall flexible, over its full height. The liner must be suitable for pellet flue gases (temperature, condensate). Check before quoting:

• The free cross-section of the flue after lining.
• That no second appliance is connected to the same flue.
• The total height and the roof termination, which determine the useful natural draught in the event of a power cut.
• Access for the annual sweep.

Facade outlet: not in Belgium with our brands

In France, an airtight stove can discharge through the facade under a technical approval (zones 1, 2 and 3). That system does not apply in Belgium. Edilkamin manuals, Air Tight models included, require a flue that terminates at roof level and prohibit discharging directly through the wall. Buildwise gives the same instruction: no terminal on the facade. The flue can pass through the wall, but it then rises vertically to above the roof, ideally 50 cm above the ridge on a pitched roof and 2 m above the parapet on a flat roof.

There is no Belgian installation standard for stoves. NBN B 61-002, often quoted, covers central heating boilers below 70 kW and excludes appliances that only heat the room they stand in. The useful references are NBN EN 15287-1 and -2 (design and installation of chimneys), NBN EN 13384-1 (calculation) and NBN EN 1856-1 and -2 (metal chimneys), plus the manufacturer's manual and the municipal regulations.

Without an existing chimney, the clean solution is an insulated twin-wall flue, inside or along the facade, run up to the roof. An airtight model keeps all its advantages: it draws its air from outside and does not depend on the ventilation of the house.

Three questions to ask the customer

1. Is there an existing flue, and where does it terminate?
2. Where will the stove sit relative to the flue: against the wall (rear outlet) or offset (top outlet with a tee and a horizontal run)?
3. Is there mechanical ventilation, an extractor hood or another combustion appliance in the house?

The answers fix the model (airtight or not), the version (rear or top outlet) and the length of flue to allow for.

A note on clearances

Every manual, and the model's declaration of performance, gives the minimum clearances to combustible materials at the rear, on the sides and at the front. They vary a lot from one appliance to another: 0 cm at the rear, 15 cm on the sides and 80 cm at the front for a Cherie H Evo; 10, 15 and 80 cm for a Cherie Evo Air Tight; 30 cm at the rear and on the sides for a Girolami Soft, with 1.50 m clear in front of the glass. Never work from an "average" value: take the one for the model being installed. On a timber floor, Edilkamin recommends a floor plate that spreads the load; also check the load-bearing capacity, as a Soft weighs 285 kg. The manuals can be downloaded from every product page.