Quote:
Originally Posted by Topspinmo
Thanks for the tip! Mine was pretty clogged and I don't have wet vac anymore beings I down sized  . I like power flush and the ball valve seals off down stream from the A coil so I could use water pressure to blow it out. That drain tube does have AC fan air pressure when the fan running, but in my case years of neglect allowed clogging at the 90 degree elbows going across, then up. snake wouldn't work won't pass the elbows beings they were 3/4". |
Actually the drain tube (trap) is under negative pressure. The reason for the trap is to allow the condensate to drain under gravity pressure. Without the trap, condensate would not drain from the A coil pan because of this negative pressure. The condensate trapped in the trap allows the condensate to gravity drain.