I received a welcome question last month from a reader about cleaning the drain lines and am going to take a break from the next system in this year’s series of attic articles. I love readers sending e-mails with questions! So let’s follow up that article and talk about cleaning the drain lines. And do I ever have a story for you that just happened a few days ago while I was on an inspection.
While inspecting a 20-year old house last week, I noticed the house next door had a problem. There was noticeable rust on the exterior walls front the ground all the way up to the second floor soffit One of the air-conditioning system secondary drains lines was dripping, almost running. If there is ever water dripping out of any of the drain lines, there is a problem with the equipment to which that drain line is attached. It appeared to have been running for a long time, and the homeowner actually had placed a large potted plant under it to get watered.
I knocked on front door of the house, introduced myself, and asked if they trusted me to come inside, I would be glad to go up into the attic to take a quick look at the air conditioning system. Sure enough, there was almost an inch of standing water in the overflow pan under one of the evaporator cores – yikes! That situation could wind up disastrous and costly with the entire ceiling falling in from water damage. I encouraged them to call an HVAC company immediately to take care of whatever needed to be done to correct the problem.
So how do you clean your drain lines? Let’s start with the drain pans and then talk about the drain lines. There are overflow pans under the water heater(s) and the evaporator core(s). Simply clean out any trash and insulation that may be in the pan. A shop vac works great to vacuum the pan clean. And make sure that the port to the drain line is not blocked with the water heater or anything next to it.
The Water Heater Drains…
The water heater drain lines typically do not get clogged up. We’ve already mentioned to keep the overflow pan cleaned out. Unlike the HVAC primary drain, the water heater drain lines do not have water running through them that can create slime or attract debris. If a water heater line is clogged up, it could be from a mud dauber filling up the tube with a mud nest. The TP&R valve should be opened at least once a year to keep it in good shape. Water from the TP&R valve is under high pressure and will keep the drain line clear. If water runs out the drain tube, the line is clear.
The Evaporator Core Drains…
The primary drain line has water running in it continually, and algae, mold, slime, etc. can build up in the drain pipe. If you have an annual maintenance contract on your HVAC system, the technician should make sure the drain lines are clean as part of the routine inspection and service. For the do-it-yourselfer, you can pour a cup of bleach down the drain line in the attic once or twice a year. In addition, you should check the sink trap to which the drain line may be attached. Fill the sink and see if it is draining effectively. If not, clean out the sink trap as needed. If the drain line is attached to a stand pipe in the attic, this is an old-style method, but still a current installation in many homes. You can pour bleach in these lines as well.
To ensure that the secondary drain lines are clean, it’s a good idea to put a piece of screen on the end outside to prevent mud daubers from entering from the exterior. You could use an air compressor and blow air into the drain line to blow out any debris. You can use a “drain gun” to clean out drain lines also. It’s a device that uses a CO2 cartridge to blow a blast of air into the pipe and force out any obstructions. Do a google search for a “Drain Gun,” you’ll find it easily.
Keep your overflow pans clean and maintain your primary drain evaporator core drain line. Keep those drains free-flowing and drain pans in good clean condition my friend. And don’t ever put plants under a dripping pipe… please get the problem fixed immediately.
