Greetings,

Our second floor condo central a/c unit is not dripping the condensing outside. The water sits in the pan (inside) and does not drip out. We end up going downstairs and using a shop vac to suck out the sitting water.

We also tried using those algae tablets and liquid, but none has pushed the condensation downstairs. An a/c repair company came out, but could not find the problem. Before calling someone else, we would like to know:

a) Maybe there is a clogged pipe or line somewhere... what could be causing it? If you think it is freezing, please note that we have visually checked the unit/pipes, but saw no indication of freezing. The a/c continues to work normally even though the pan becomes full and starts to leak inside. Why is the a/c NOT dripping outside normally... what could be causing the problem?

b) If there is a clogged pipe or line, then why does the shop vac get the water out (isn't it true that if a pipe/line was clogged, NOTHING would go through?)?

c) Would it be safe to use a snake to try to unclog the system (if that is the problem), if yes, where should we snake it from (the outside pvc pipe where we vacuum the water out of)?

Thank you greatly for your response.
- Lee

Clean the opening from the pan to the drain. It is clogged. You can use air pressure to blow it open as well

Is there a trap on this drain line ? Some times the air handler will suck air through the drain and into the air handler thus pulling the water away from the drain and will only drain when the fan is shut off, check filter and coil for dirt which will cause the fan to pull harder through the drain line, good luck, Mike