---------------------------------------------------------- AeroElectric-List Digest Archive --- Total Messages Posted Sat 02/28/26: 1 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 09:34 PM - Re: Fuel System Manager (Eric Page) ________________________________ Message 1 _____________________________________ Time: 09:34:50 PM PST US Subject: AeroElectric-List: Re: Fuel System Manager From: "Eric Page" 911pete wrote: > The HPFS can stay open in Auto. It just needs to be closed in the off position. In that case, Joe's schematic has you covered. His design should be easy to wire "in the air" using a chassis-mount relay like this one... https://www.digikey.com/short/bh10z8v9 ...which has the advantage of being easy to replace if it ever fails. 911pete wrote: > Im using the Garmin G3X with a GAD27. [ . . . ] Either of these units can be configured for the warning to be active high or low. OK, I've made it active low. If you change your mind about avionics it will be compatible with anything on the market. ----- The schematic, wiring diagram and functional description are attached to this post. All parts are through-hole, so assembly will be easy. The bill of materials is here: https://www.digikey.com/en/mylists/list/CFEKJK5A1K For anyone else who's following this thread: please critique my schematic. The more eyes on it the better; let's find my mistakes at zero altitude and zero airspeed. NOTE: I assumed that the fluid detection sensors have open contacts in the absence of fluid and closed contacts in the presence of fluid, that the "C" (common, white) wire of the sensors will be connected to 24V and the "NO" (normally open, brown) wire will be used to signal downstream circuits. So, if fuel is detected then 24V will be present on the brown wire, and if fuel is not detected then the brown wire will be open circuit. When everyone's happy, I'll turn this into a circuit board layout. Read this topic online here: http://forums.matronics.com/viewtopic.php?p=516900#516900 Attachments: http://forums.matronics.com//files/low_fuel_warning_module_rev_a_286.pdf ------------------------------------------------------------------------------------- Other Matronics Email List Services ------------------------------------------------------------------------------------- Post A New Message aeroelectric-list@matronics.com UN/SUBSCRIBE http://www.matronics.com/subscription List FAQ http://www.matronics.com/FAQ/AeroElectric-List.htm Web Forum Interface To Lists http://forums.matronics.com Matronics List Wiki http://wiki.matronics.com Full Archive Search Engine http://www.matronics.com/search 7-Day List Browse http://www.matronics.com/browse/aeroelectric-list Browse Digests http://www.matronics.com/digest/aeroelectric-list Browse Other Lists http://www.matronics.com/browse Live Online Chat! http://www.matronics.com/chat Archive Downloading http://www.matronics.com/archives Photo Share http://www.matronics.com/photoshare Other Email Lists http://www.matronics.com/emaillists Contributions http://www.matronics.com/contribution ------------------------------------------------------------------------------------- These Email List Services are sponsored solely by Matronics and through the generous Contributions of its members.