I had the lines of my Mitsubishi mini-split run through the walls and they exit to the exterior at the floor plate. The installer did put a plate over them to protect screwing or nailing into them. If you have to get to them...replacing some drywall is not a big deal...but unlikely any issues with lines.

homebound.... Could you tell whether the clog was from build up or an object? Just a suggestion below since I know you do this type work. It won't increase your repeat business but will surely keep your customers happy. If it's build up (especially if they have a disposal), I always suggest folks maintain a maintenance schedule using one of the liquid enzyme drain cleaners similar to that "Roto Rooter" provides after a cleaning. It can be purchased at Home Depot or Lowes far cheaper. The stuff actually works like the picture on the bottle!!! It also deodorizes the disposal if they have one and is septic system safe (actually good for septic tank too). I suggest that for the first week, before everyone leaves the home for the day, pour some in all the drains followed by 3 cups of water. Then do it again that night before going to bed. After the first week, do it again on a weekly basis and especially if going away on vacation. Then go for a monthly regime. I personally prefer the weekly regime. I'm not one for monkey snot additives. We actually tested this stuff on a system over a period of one year and after opening the system up for inspection we found it surely does what it says it will.

Drum rrrrroooooolll...:) Well after 6 weeks of stalling I finally got er' done! My first attempt to drain the tank did good, I used the "siphon water out thru the cold or hot lines" method. The only glitch was that the 1/2" insertion pipe was too large, it went in about 3" and stopped, it wasn't crud but a junction point, maybe. Used 3/8" and did ok, took over an hour to empty. The odd thing about it was that as it was emptying (thru translucent pex line) I used a flashlite shining thru the line and did not see much crud getting sucked up, guessing most is rock hard? Thanks for the support to All of you! In a nutshell it was just 3/8" pex connected with an L to a 1/2" water hose (super glue and clap :) The end of the outflow was 5' lower than the WHeater. The best way to get the siphon started was to force water (via another hose) up the line until it comes out at the WH end, then shout to wife to unplug the water and immediately insert the 3/8" pex end into WH, I used the hot outlet, worked a-ok. Thanks again for the help!

We initially thought it was calcium build up, but of course, it's distilled water - there shouldn't be any calcium in it. The condensed water is clean no matter what temperature it condense at and probably very clean. Condensing is a layman engineering term as the liquid considered in balance # molecules leaving equal to number of entering the liquid. With condensation more molecules enter the liquid and than leaves. = The water in your condensate drain in no way as clean as distilled. First there is a debris and dust as the water drips over dusty coil and washes rusted drain pan; than there could be bacteria if pipes stay wet or drain pan, than evaporator coil coatings, at 15 years also contains rust and mechanical .., it could contain some minerals in your air. Can it clog up drain line? Of course after 15 years most definitely.