Baxi 5111414 Pressure Switch (6511p) Product Information: The Air Pressure Switch, also known as the APS is used as a safety instrument to ensure the fan is fully operational. The fan prevents a build-up of toxic gasses within the appliance, venting the fumes out of the property safely. The air pressure switch is tracked by the printed circuit board (PCB), ensuring that it is in service; if the air pressure switch is not operating correctly the PCB will restrict the appliance from firing up. Brand: Baxi
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