A pellet boiler often reports a draught error before the owner notices any soot. We clean the flue pipe, the T-piece connection with the condensate collector, and the chimney or liner along its whole length. Cleaning one flue costs from €100, certificate included.
What is different in a pellet boiler flue
- Fine ash: pellets burn almost completely, but the fan blows the light ash into the flue pipe, where it settles in the horizontal sections and bends.
- Cool smoke: a modern pellet boiler gives most of its heat to the water, and the smoke in the chimney is cooler than with a wood boiler.
- Condensation: the moisture in the cool smoke condenses on the flue walls. In a wide masonry chimney without a liner it soaks into the bricks, and dark patches appear on the outside.
- Fan and tight joints: many pellet boilers push the smoke out with a fan, so the flue pipe joints must be airtight, otherwise smoke gets into the room.
- Electronics: the boiler shuts down with an error if the draught is too weak, so a clogged flue often shows up as a boiler fault.
How we clean a pellet boiler flue
- Boiler switched off and cooled down We switch the boiler off following the manufacturer's procedure, so that the fan does not start during the work.
- Flue pipe and T-piece connection We open the cleaning doors, remove the ash from the horizontal sections and bends, and clean the condensate collector.
- Liner or chimney We clean a stainless steel liner with a plastic brush of the right diameter so as not to scratch the surface. We clean a masonry flue with a brush from the top or from the bottom.
- Joint check We check the seals and joints: whether there are traces of soot that point to a smoke leak, and whether condensate is running out through the joints.
- Certificate We record the flue material, its condition and our findings in the certificate, for example moisture in the brickwork or damaged seals.
The owner usually cleans the boiler burner, heat exchanger and turbulators following the instructions, or the boiler service does it. Our job is the flue from the boiler outlet to the chimney head.
An old masonry chimney and a new pellet boiler
Problems most often start when a pellet boiler is installed in place of an old wood boiler and connected to the same wide masonry flue. The smoke cools in it, condensation soaks the brickwork, and after a few winters the joints crumble and the draught becomes unstable. When the boiler is replaced, a certificate on whether it may be connected to the flue must be drawn up before the new appliance is used, and the conclusion is often that a liner is needed. More on this: chimney lining and condensation in the chimney.
Cabinet Regulation No. 238 “Fire Safety Regulations”, point 79: when a heating appliance is replaced, a technical condition inspection certificate is drawn up stating whether the appliance may be connected to the flue. Source: likumi.lv, checked 04.11.2026. Regulations checked 04.11.2026; from 2 January 2027 they will be replaced by new fire safety regulations, which we will check as soon as they are adopted.
How often to clean a pellet boiler flue
The regulations define a long-burn appliance as a solid-fuel appliance that does not store heat for longer than three hours. A pellet boiler does not store heat, so it is advisable to clean its flue the same way as a wood boiler flue: by 1 November and again between 1 November and 1 March. If the boiler also heats hot water in summer, ash builds up all year, and it is worth checking the flue pipe between cleanings too.
Cabinet Regulation No. 238, point 68 (long-burn solid-fuel appliances). Counting a pellet boiler as a long-burn appliance is our reading of the definition in the regulations (does not store heat for longer than three hours). Source: likumi.lv, checked 04.11.2026.
How much pellet boiler flue cleaning costs
Pellet boiler flue cleaning costs from €100, usually €100–130, with cleaning of the flue pipe and condensate collector, the certificate and call-out in Riga and the Riga region. The price depends on the length of the flue pipe and the number of bends, the height of the liner and access to the chimney head. If seals or a damaged liner section need replacing, we price that separately and do it only with your agreement. All prices: prices.