I use high temp silicone rubber tubing rated to 450d to connect to the pitot lines, I think you would be fine with 6" tubes.
The GAP 26 has an Operating Temperature Range of -55° C to 240° C (464F) so I doubt the lines come even close to that temp.
Hello caapt,Once again, I should have read the directions before I cut. Garmin says the 3/16 AU tubes should be a minimum of 8 inches. Mine are about 6. Any ideas. Garmin says to flare the tube and add a fitting.
I was firing up my GAP 26 heated pitot (plain heated, no controller) on the test bench to test the heating elements. After having it on for 20 minutes I could still grab the tubes at 6" no problem. It only got really hot within 1.5" of the pitot body. The pitot body was too hot to touch.