Dead head return line questioning

[Bmaughan]

Is there ever a circumstance where fuel could be drawn from the pre-regulator return line ( on a dead head setup ) instead of the feed. I was just sitting here thinking about the fuel system and realized I used ptfe tape on my mechanical and analog pressure gauges, which I know is a no-no for fuel lines but I figured since it was on the return side and I have duel filtration with this setup I would be ok.
I can’t think of any situation where fuel could be pulled back from the deadhead return line, since the feed should always be pressurized before any fuel is consumed, but I just wanted to see if anyone else had any thoughts

??

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[Kona 18]

Fuel that has entered the return line cannot make its way back into the feed. Fuel will take the path of least resistance and that is the return line bc it has very low pressure in it compared to the feed line. Teflon tape should never be used on AN fittings, the only thin that used teflon in a fuel system is

1) fuel pressure gauge 1/8 NPT port
2) any NPT ports you plug using plugs(eg extra ports on rails

Everything else in a fuel system is either ORB, so sealed by O ring, or AN, sealed by mating surface

 

[Bmaughan]

Fuel that has entered the return line cannot make its way back into the feed. Fuel will take the path of least resistance and that is the return line bc it has very low pressure in it compared to the feed line. Teflon tape should never be used on AN fittings, the only thin that used teflon in a fuel system is

1) fuel pressure gauge 1/8 NPT port
2) any NPT ports you plug using plugs(eg extra ports on rails

Everything else in a fuel system is either ORB, so sealed by O ring, or AN, sealed by mating surface

Ok great... this is what I thought. Thanks for confirming!

 

[illtal]

Is there ever a circumstance where fuel could be drawn from the pre-regulator return line ( on a dead head setup ) instead of the feed. I was just sitting here thinking about the fuel system and realized I used ptfe tape on my mechanical and analog pressure gauges, which I know is a no-no for fuel lines but I figured since it was on the return side and I have duel filtration with this setup I would be ok.
I can’t think of any situation where fuel could be pulled back from the deadhead return line, since the feed should always be pressurized before any fuel is consumed, but I just wanted to see if anyone else had any thoughts

??

Did you use any Loctite/Permatex for fuel fittings?
https://www.permatex.com/products/t...d-sealants/permatex-thread-sealant-with-ptfe/
https://www.henkel-adhesives.com/us/en/product/thread-sealants/loctite_542.html

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