ORIGINAL: roger.alli

It should be remembered that no matter what size the UAT is , the pressure differiential between atmosphere and the inside of the fuel system, is dependant upon the ENTIRE fuel system upstream of the pump. In other words you need to ensure that the entire fuel system is sized correctly, right from the, breather to the pump.

I think that the problem that many people have had with UATs collapsing, is not because the UAT is too small, but the ENTIRE fuel system has created too much pressure drop. This manifests itself when the UAT collapses, because the UAT is the most flexible part in the system, and is close to the pump, where the maximum negative pressure is.. Small fuel lines, and tank fittings with small orifices need to be avoided, especially in a high flow fuel systems..


Roger