This thread has perfect timing and great info for me.
I was thinking of ditching my setup and simplifying it, but it looks like every system is a compromise.
I just mounted a belly radiator which entailed moving the pumps & sump tank. As other local pilots had commented on how complex my fuel system was I thought it opportune to address it now. After following this thread though I'm inclined to stick with this setup now as I know it works. and just not let anyone else on the controls.
Only problem I have is I cannot tell the fuel level in the sump tank. Need some sort of warning that I've drained a tank dry or have a vent or feed problem. Am thinking of putting a sight glass in the return line from sump to fuel selectors for a visual clue.
I like this setup as it allows me to feed from any or all tanks. not needed but usually leave 1 transfer pump on. if both transfer pumps happened to fail the fuel return path gives a free flow path from tanks to sump also.
I have managed to empty the sump tank once when flow testing the system but there was no back pressure on the system so regulator was not circulating fuel. I guessed the tank vent lines (1/4") are just to small when fuel flowing at 180l/hr and it vapourized in the sump.
Steve. I'm interested to know the model No. of your fluidyne oil cooler. I started with these mods because I couldn't control my oil temps, so new belly radiator installed to give oil cooler all the cowl air, but I never thought that the mazda cooler may be blocking oil flow. Whats the clue that the front relief valve is opening?