Fans
The fan on a boiler helps to drive harmful gases out of the flue as well as bringing fresh air oxygen into the boiler without the fan, these gases could linger and become dangerous, the operation of the fan on a boiler is important, the boiler won’t fire up until it recognises that the fan is operational.
These fans come in two categories:
The first category is a 240V driven fan, these fans were fitted to the older non condensing boilers and only have 1 speed, so they are either on or off.
The second category is a DC-driven fan, these fans are fitted to the newer energy efficient boilers and can have their speeds varied and regulated via the printed circuit board PCB.