So I've been having a leak in my AC handler. A lot of water was dripping into the drain pan which eventually hit my float switch. I recently moved into the house and the AC unit is 10 years old (sears brand). I shop vac the water out and called a plumber.
The plumber came and said that he sees no crack in the coils or primary pan in the handler. But couldn't really figure out why water would drip out of the handler. He thought the drain as clogged and so he blew it out. Days later, still dripping. It was starting to now drip from my ceiling in the attic. Not good. I called another plumber who came out and said that I have a negative pressure system and that my drain line is not vented properly. I think he said I didn't even have a vent installed. So he installs the vent and re-pitches the drain pipe. He said that it would still drip because the interior of the handler was all wet with water and would take time to dry out. That was yesterday morning.
However, by yesterday evening, I was actually getting more water in the pan and coming from my ceiling. I went into the attic and saw that the first plumber removed the "P" trap from the drain. The plumber added a vent pipe but got rid of the p trap. I called another plumber out for an emergency last night and he added the p trap back and that seems to have worked. He suggested running the fan continuously for a while to help dry out the ac insulation inside the handler so that the water stops dripping from the insulation.
However, when I looked at the re-piping he did, he moved the vent pipe before the P trap. Everything I have read states that the vent has to come after the P trap. Is this going to be a problem? I've spent quite a few dollars on these plumber visits and can't spend any more money on this especially where the AC handler is apparently in good shape but just a matter of not having been piped correctly. I called the plumbing company and, of course, they tell me that there is nothing wrong with the piping.