[retiredguy123]

Originally Posted by DrHitch

Has anyone hooked up a line from hot water supply to "blast" clean that AC condensate line?

Yes, would require a backflow shutoff valve and a bit of plumbing. Surprised that AC installers haven't suggested this method ...but, agree that the monthly manual flush works just fine!

The easiest way to accomplish what you suggest is to buy one of these from Amazon.

Amazon.com

It just connects to a garden hose and no backflow preventer is needed. I have one and it works well, but you do need a second person to make sure the device stays inside the pipe.

[Iowatransplant]

Hook a garden hose to the sink in the garage (some models may not have a garage sink) and attach a laundry washing machine hose with one end cut off. (the washing machine hose is smaller diameter and fits in the condensate line. Turn on the hot water and let run for a couple of minutes. Does a great job of cleaning out the line!

[retiredguy123]

Originally Posted by Iowatransplant

Hook a garden hose to the sink in the garage (some models may not have a garage sink) and attach a laundry washing machine hose with one end cut off. (the washing machine hose is smaller diameter and fits in the condensate line. Turn on the hot water and let run for a couple of minutes. Does a great job of cleaning out the line!

The device in Post No. 16 is easier to use, and it seals the condensate pipe to the device, so there is no backflow. You just stick the rubber part into the condensate drain pipe and turn on the hose. Note that, by code, there is no garden hose connection to the laundry sink faucet, so you would need to rig up a connection adapter. In my opinion, cold water from an outside hose bibb works just as well as hot water, and there is no risk of contaminating your potable water system with a backflow into your house.

I will add that it is never a good idea to connect a hose to an inside faucet because there is no vacuum breaker to prevent backflow. That is why inside faucets do not have hose connections. Outside hose bibbs have a vacuum breaker to prevent backflow.

[lauron57]

Originally Posted by DrHitch

Has anyone hooked up a line from hot water supply to "blast" clean that AC condensate line?

Yes, would require a backflow shutoff valve and a bit of plumbing. Surprised that AC installers haven't suggested this method ...but, agree that the monthly manual flush works just fine!

It's NOT recommended to flush the drain pipe with any method that could pressurize it because the drain pipe joints may not have gotten glued 100% and it could be forced apart underground or even under the concrete somewhere. The recommended method is to vacuum from the outside. That being said, I keep mine clean with this method, which should have minimal risk because of the frequency I do it. At the first of every month I connect a short hose from my hot water tank drain and run some through it. This accomplishes two things, regular flushing the AC drain and the water heater. I also put a bucket under the outside drain to monitor the deposits coming out of water tank. I use that to determine how much water to run through it.

[NoMoSno]

Originally Posted by DrHitch

Has anyone hooked up a line from hot water supply to "blast" clean that AC condensate line?

Yes, would require a backflow shutoff valve and a bit of plumbing. Surprised that AC installers haven't suggested this method ...but, agree that the monthly manual flush works just fine!

If I did a new build that is exactly what I'd do. Would just need two regular ball valves. Much easier than dragging a hose out with the rubber bladder. The advantage would be a hot water flush by just closing one valve and opening another.

[Michael G.]

Would a couple drops of dawn dishwashing soap added to hot water help lube the cleaning process?

[collie1228]

Originally Posted by DrHitch

Has anyone hooked up a line from hot water supply to "blast" clean that AC condensate line?

Yes, would require a backflow shutoff valve and a bit of plumbing. Surprised that AC installers haven't suggested this method ...but, agree that the monthly manual flush works just fine!

I have been using white vinegar in my drain line every time I change the filter, which is 2-3 times a year. Last year the line plugged, so I hooked up a hose to the line (cold water) and ran it for a minute or two. You wouldn't believe the pile of nasty grey matter that came out at the end of the drain. It was disgusting. Now, once each summer, I will run water through it along with the vinegar treatment.