Ferroli Air Pressure Switches
This pressure switch is designed to detect if the operation of the fan and is connected to the fan via heat resistant pressure tubes directly onto the fan venturies. This enables the printed circuit board to detect when the fan is running because air flow from the fan closes the air pressure switch which in turn sends a signal down to the pcb confirming the fan is running. At this point gas can be sent to the burner and the ignition process can begin.
If the fan was to stop running or jam there would be a lack of air flow across this air pressure switch which would cause the air pressure switch to open. A signal is then be sent to the printed circuit board instructing the Ferroli boiler to stop sending gas to the burner and to turn the boiler off. This Ferroli air pressure switch is a fundamental safety device ensuring the safe running of the boiler.