Efficiency & reliability

Weather and wind conditions can vary drastically over the course of a year leading to a wide range of draught conditions in the chimney. On cold days with high wind conditions, the draught increases, while on calm, warm days there may be no draught at all. This leads to different draught conditions inside the fire chamber as the burner fan will give different amounts of air depending on the conditions. A properly dimensioned and correctly installed draught stabilizer will automatically and continuously allow only the necessary amount of combustion air to pass through the boiler resulting in an optimal efficiency rating.

Draught variations in the chimney influence the velocity of the exhaust fumes as they pass through the boiler, which effects heat exchange. For example, if draught conditions are too high when burning solid fuels, the time for carburetion and contact with the heat exchanger is too short, which leads to low thermal efficiency, poor combustion and eventually even problems in operation. Simply put, without a proper draught stabilizer, much of the heat produced in the boiler will be lost through the chimney.

Energy savings

The biggest energy losses in installations without draught stabilizers arise due to increased soot build up, breakdowns and unburned particles. Experience has shown that the total yearly savings for an installation with a properly designed and installed draught stabilizer is up to 10%, depending on various conditions. 

Irrespective of whether the boiler is fired with oil, gas, pellets or wood, a stable draught in the chimney is important for combustion conditions in the burner chamber.

Prevent condensation

Condensation in chimneys can occur due to a number of various factors. The condensation that runs along the inside walls of the chimney consists mainly of water, but also contains corrosive acids. This is extra sensitive in a brick chimney since condensation leads to erosion and cracks from freezing.

The material in a chimney always maintains a lower temperature than the exhaust gas. It is important that the exhaust gas temperature is at least 10° C (50° F) above the dew point temperature when measured at 0.5 m (20") from the top of the chimney.

Installing a Tigex draught stabilizer will allow dry air from the boiler room to enter the chimney. This provides a certain amount of dilution to the exhaust gases during operation, which increases exhaust gas circulation and decreases the dew point by approx. 10° C (50° F) . This also provides a certain amount of drying while the burner is in stand by position.

Dew point

(temperature at which steam in exhaust gas starts to condensate)

The dew point temperature varies depending on CO₂ content - the lower the CO₂ content, the lower the dew point.

Draught stabiliser location

The optimal placement depends mainly on the task it must fulfil. Possible placements include; on connection pipe directly after the boiler via an adapter for round pipes. It is possible to build it in the brickwork above the boiler or under the flue pipe. Special adapters must be used in the latter two cases for building into brickwork.

Always install a Tigex

A large number of domestic oil boilers that are sold today are replacements for older heating installations. They are often connected to old chimneys and/or chimneys with insufficient insulation. These older chimneys often have an open area that is too large for today’s modern and efficient boilers. When changing from oil heating to wood or pellets, the problem is often the opposite since smoke gas volumes increase when burning solid fuels, demanding a larger area.

The best solution is to install a correctly dimensioned stainless steel pipe in the chimney in combination with a Tigex draught stabilizer. Installing only the stainless steel pipe without a Tigex would make it impossible to regulate stable combustion conditions in the burner chamber throughout the year. Not using Tigex also increases the risk of condensation.