Noise, weak airflow or a pellet stove that shuts down
Rumbling, squealing or a scraping sound typically comes from worn bearings in the fan motor. A fan that sounds normal but only provides a weak airflow is often coated with dust. The tangential fan's long roller collects dust between the blades, causing both reduced airflow and an audible imbalance. Clean the roller and air ducts with a soft brush or a vacuum cleaner before ruling out the fan. Brushes and vacuum cleaners for this purpose are available under cleaning and maintenance.
If the stove shuts down due to overheating even though it burns normally, this is a sign that the fan is not moving enough air. If it is a centrifugal fan that hums without starting, the capacitor may be the cause and can be replaced for a fraction of the price of a new blower. Note that the fan on most pellet stoves only starts once the stove has reached a certain temperature, so it is normal for it to remain still during the first minutes after ignition.
The fan only controls the air out into the room. If the stove reports a draught error or smoke leaks out, it is the flue gas extractor, and if the pellets do not reach the burn pot, it is the gear motor. If you cannot determine which motor is causing problems, the overview of motors and fans provides a complete overview.
Long roller or round scroll housing
The two types are easy to tell apart. A tangential fan is a long, cylindrical roller with blades and a motor at one end, and the air is blown out through a narrow, elongated outlet. A centrifugal fan has a round housing resembling a scroll housing, with a wheel inside and a nozzle through which the air is forced out.
Tangential fans are available both as universal models and for specific brands, while centrifugal fans are matched to the pellet stove's brand and model. For certain models, the centrifugal fan is mounted on a flange that can be purchased separately if the old one is damaged.
Four details on a universal fan
A universal tangential fan must match the old one in four respects. The length ranges from 15 to 48 cm and typically corresponds to the length of the outlet. The rotor diameter is 5, 6 or 8 cm. The height of the outlet also varies, and at the same length there are, for example, both 240 x 34 mm and 240 x 45 mm. Finally, the motor must be on the same side as on the old one.
The last point is what most often goes wrong, because two fans can have identical dimensions and mirrored motors. Note which end the motor is on, viewed from the outlet, before removing the old one, and compare it with the product image. The motor may also have a different shape, and some models have a round motor instead of the more angular standard motor.
