Is the PVC pipe glued together? If is is not then you could disassemble it and clean out those pieces, You can also try pouring water down the open tube and see if it flows out back of the house freely. If it does then the clog is further up the line towards the coil. The PVC pipe will have to be cut, cleaned, and replaced,

It is difficult to say how much it will cost to fix this. If you do call in someone have them install a P trap. The open pipe is allowing air to leak from the condenser and is not helpful to eliminate clogs. I recommend installing a clear EZ Trap so you can clean it yourself in the future.

This HVAC unit is really not properly installed as the over flow condensate is simply plugged at the E-coil so when the primary line gets clogged, the condensate water will run down inside the furnace to the floor... and there is no emergency pan to catch that water.

I've seen shorted out circuit boards, blower failure due to condensate drainage problems. The costs only go up if you don't fix this right.

I service the Katy, Texas area.