ORIGINAL: lov2flyrc
There has been argument that Festo fittings will leak under suction never to use them on the suction side. NONSENSE! The Festo quick star fittings are rated for about -20psi. I have never had one leak. Square cuts of the tubing is key for good seal in the QS fittings.
Todd
Attached is the Festo spec sheet for the 6mm Festo Ball valve. The valve is rated at 10 bar (145 psia) of positive pressure and 1 bar (14.5 psia) of vacuum pressure. So, when the valve is placed on the suction side of a fuel pump then its only good to 1 bar of suction pressure. Having seen how a P180 or P200 sucks in the sides of a BVM UAT, I would think that it is pulling more than a 1 bar vacuum.
We lost a jet at Miss Afterburner this weekend due to a flameout. We found the CAT empty and all fuel lines/connections full of fuel and secure, EXCEPT, the fill line which was dry. The guy had installed a 6mm Festo valve in the fill line. We concluded the P-200 had sucked air through the Festo fitting. I can't say for sure that the fill line was securely pushed into the fitting but it was cut squarely.
I've used Festo's on the suction side myself without problems but after this incident, I'm not so sure.
Craig