The switch is normally closed. When the pump is making pressure the light is off. When the wing tanks run dry, or when the pump fails, the light comes on. The reason for the light is that the pump is not designed to run dry for long periods of time.
If your switch is NO it is not the right part. John Cooper Skyport Services www.skyportservices.net -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of hogowner82 Sent: Thursday, July 30, 2009 1:49 PM To: [email protected] Subject: [ercoupe-tech] HEADER TANK O-200 I still trying to understand how the electric fuel pump transfer system is supposed to work on the O-200 conversion. The placards say, "Turn on to keep nose tank full", and "Fuel transfer pump warning. Turn fuel transfer pump off when light is on". I understand that the fuel pump is supposed to run continually while in flight to keep the header tank full. The warning light is wired from alternator positive, through a 4psi normally open pressure switch to ground. So as long as the pump is transferring fuel to the header tank, the light should be on. When the wing tanks are empty, the flow will stop, the pressure drops and the light goes off. Is the placard wrong, or am I missing something? ------------------------------------ Yahoo! Groups Links
