Today, while getting ready to pour vinegar down the HVAC drain, a simple setup occurred to me. There are many plant watering devices that can pump water for as little as 5 seconds and at intervals spanning many days. Here's one example:
I am going to get one of these and test if I can get it to periodically squirt vinegar down the HVAC drain. While it will not be controlled by Hubitat, if it drips a couple cups down a month, it will keep my HVAC drain clean, and that will be one less task for me to do manually every month.
Going to set this up later this week, and I'll update this post once I determine the right length of time for the pump to be active.
Plant Watering device may work. But these things are using impeler-based pumps which depend on exact setup could be leaking (i.e. may siphone liquid in one or the other direction). Also the amount of liquid is somewhat random (this could be OK) and there is no "low liquid level" warning.
Could always go with a premade setup, maintenance free for 3 to 6 months. More expensive but looks well worth it. No nasty vinegar either! lol Doesn't have any smarthome intergration but can do a manual (extra) cleaning through their app.
Mostly the problem is with gravity drains. If you have long drain lines or elbows it's more of a problem. Greater likelyhood in Florida etc. They get biofilms. Older systems that output rust flakes will clog a gravity system.
I have a garden hose mount on my attic hvac system that has a 250 foot drain line. It has a ball valve between it and the air handler. You close the valve and flush the line with the pressure from the hose. I'll typically put a powerful line cleaner down it the day before.
Using a trap on the line helps with the rust problem.
Minnesota here - I too have never done the drain pan (and mine's all but inaccessible [cramped space, taped seams, etc]), but as Dan said, the condensate line is definitely something to watch.
The water may look clear coming out the other end, but gunk in the line could eventually even block it.
Yes, I always get some chunky stuff out of the line. The line will normally flow clear water, as the gunk builds up on the inside walls of the PVC pipe. The vinegar helps to kill and dislodge this material.
FYI - This is a great video showing why a trap is required to allow water to flow out of the unit while the system is running. Pretty cool physics example!
Same. Except 40 years. I do get twice yearly HVAC preventive maintenance, but to my knowledge, the lines have never been flushed.
I just got an endoscope camera with a long cable so maybe I'll take a look inside the pipe. (In other words, I have a hammer and that pipe looks like a nail to me.)
I use those same traps. I like them because you can see the material, the caps come off and you have a brush to clean them out. Plus they have a shutoff in the top cap you can wire in if you get that option.
I typically use a shop vac a few times a year to suck out any stuff in the drain line. I hook it up to the line outside, add some painters tape to create a seal, and let it run for a few minutes. If it has been a while since doing this maintenance, I get a bunch of stuff out of the line. Easy to see in the shop vac's canister.
I have neglected this maintenance in the past and it has bitten me. My secondary drain line simply dumps into the pan under the air handler unit. The pan fills up, trips a float switch, which then kills the 24VAC power to the system. Now I have gallons of water in the attic that needs to be removed with the shop vac. Much easier to perform the routine maintenance!
Tablets when you change the filters in the trap do the same thing. But I certainly get why people would buy that thing. I've seen the destruction condensate lines can do to high end homes. Couple hundred a year is nothing.
)
