Z Flex Improper installation

[Jon mackay]

Here are some pictures of a wrong installation of z-flex vent.
No condensate trap.
Too low to the ground.
Installed flush with wall at exterior.

[Bob Harper]

Z-vent---not Z-flex.

Why is it improper? Have to found this in the listed instructions of either the appliance or vent mfr.? Many high eff. gas appliances prefer condensate to drain back into the unit rather than deal with the restriction of a condensate tee.
HTH,
Bob