View Full Version : Something is leaking from my Furnace?

Mar 26, 2005, 08:45 PM
Came home and found pools of water in my basement, it surrounds my furnace and water heater.. It seems to me that it is coming from my furnace, could this be? I didn't know water could come from my furnace. How can I fix? I don't know too much about this type of thing, so if you could tell in layman terms would be greatly appreciated.

Another item, I know that a "pump" sits next to my furnace and water heater, I checked this pump to see if there is any water coming from it, there wasn't.

I have vacumed up the water and have a dehumidifier running right now.

Please help>

Mar 26, 2005, 09:07 PM
You might get a small amount of water out of a forced air furnace in very cold weather if the moisture in the combustion products condenses, or from an air conditioner coil in warm weather. If you have a hot water system, a pump near the furnace pumps hot water around the house. Such a system could develop a leak inside the furnace or boiler causing large amounts of water to leak out. Forced air usually has large ducts leading to holes in the floor covered with metal grates. Hot water systems has small, round pipes leading to large boxes on the wall. Post back describing your system.

Mar 26, 2005, 09:23 PM
Not sure what you mean by the system, but I'll give it a shot.

I have a RUUD Silhouette II. There is a small PVC pipe about 1" coming from the Unit. This PVC pipe runs to the pump, from the pump runs a small plastic pipe to the outside to drain water I assume. Could I have a faulty pump?

I haven't run my heater for about a week or so. I haven't run my AC unit since early fall.

Now, I did turn off the warm water from the water heater to the rest of the house as a precautionary measure.

I looked, and didn't see those metal grates/boxes you described. My house is fairly old, could that be why? However, my HVAC system seems fairly new.

Mar 27, 2005, 10:32 AM
Ok, your furnace is the common forced air. The pump you describe sounds like an AC condensate pump. Making cool, dry air out of warm, humid air condenses water, and it has to go somewhere. I doubt the furnace is the problem.

It could be the hot water heater. The tank could be leaking. If you shut off the line that goes from the water heater to the house, it would continue to leak. Shutting the water from the pressure tank or water meter to the water heater is a bad idea, and often there is not a valve for it. Cold water flows into the tank to replace hot water drawn off. That water then expands as it heats and some of the water has to go somewhere even if you are not drawing any more hot water. Usually it goes back out the supply line. It can also come out the safety valve. They are near or on the top of the tank. Usually they have a lever to operate them and may have a pipe stopping near the floor. They are there to relieve the pressure before the tank blows up if something goes wrong. Some times they go bad and discharge water when there isn't a problem. I would turn the tank back on, and put a bucket or something under the relief valve and see what happens. Even if the bucket runs over, you will know the relief valve opened if there is water in the bucket. That will not tell you if the valve is bad, or another problem, maybe a stuck thermostat.

If water starts to leak out the bottom of the tank as soon as you turn on the water, the tank is bad, and must be replaced.

Have you had a lot of rain recently? Water could be coming through your foundation or down a roof vent. Wherever water comes from, it can flow to a low spot, then dry up leaving no trail to where it came in. You just have to catch it in the act, or look for moisture in protected spots.

You may need to get back again before solving the problem.

Note Labman is from Labrador Retrievers. My family socalizes service dogs.

Mar 31, 2005, 09:24 AM
Googled my problem and happened upon this thread. My furnace has been putting out water for some time. I've cleaned it up and it comes back. This only happens when the heat is on.
There is no metal grate in the floor-the pipes go into the walls. Any thoughts? Thanks in Advance!

Mar 31, 2005, 10:27 AM
Just fixed my problem. It was my water heater.


To my knowledge, the furnace should not leak a thing (according to my plumber). The only thing that should possibly leak is your a/c unit (condensation from the coils). Is your water heater next to your furnace? At first, I too thought it was my furnace because the water collected around it. I would take a serious look at your water heater if it is close by. Of course, I could be wrong, I'm no expert.

Hope this helps.

Mar 31, 2005, 12:04 PM
Googled my problem and happened upon this thread. My furnace has been putting out water for some time. I've cleaned it up and it comes back. This only happens when the heat is on.
There is no metal grate in the floor-the pipes go into the walls. Any thoughts? Thanks in Advance!

It sounds like you have some sort of a radiant hot water heat. If so, the water could be leaking inside the furnace, or as commonly called, boiler. Usually they have some removable panels, or maybe you will need to remove some screws. There should be 2 pipes going into the furnace, one water in, and one water out. Follow them through the furnace and what they connect to looking for dripping water, rust, mineral deposits, and any other sign of water leaks. Leaks are usually above wet places. Most hot water heating systems use water tubes, where an open flame heats water inside a pipe called a heat exchanger. If the heat exchanger is leaking, and the furnace is very old, you may be better off replacing it.

If the sign of water are around the vent to the outside, it could be a condensation problem, although they are most common in the very coldest weather.

Mar 31, 2005, 01:21 PM
Thanks for the replies. When I have some time (I've got an infant keeping me busy) I'll attempt to get inside the furnace and see what I can see. Although the water heater is close to the furnace there is absolutely no water around the water heater at all... not even close to it, so I will asssume it is the furnace. I'll check back when I can get inside and take a look. Also, the furnace is only about 5 years old.

Jul 20, 2005, 09:03 AM
I am having same problem, my furnace is leakink too. Although I tried to vac dry but I still see water around my furnace. I believe it is with my a/c condensation. Any thoughts how I should fix it. Thanks!

Jul 20, 2005, 09:32 AM
WEll, I thought it was just happening with the heat on but its even worse when AC is on. I've had to call a repair guy to come take a look-I'll let you know what the diagnosis is!

Jul 20, 2005, 10:04 AM
I am also seeing water when my A/C if OFF too.

Jul 20, 2005, 10:49 AM
Inside the box is what they call an ''A'' coil. It looks like 2 auto radiators leaning against each other. Water condenses all over it. It takes a while for it to all run off after the blower kicks off.

Jul 24, 2005, 06:20 PM
My furnace is probably older than I am, we have been in this house a year. I didn't have any problems last summer or the following winter. This summer however I have had a steady stream of water from the bottom of my furnace. I just took the hose off that runs to a drain in my basement and cleaned it out. I had been told that would basically fix my problem.

I am curious to here what the repair man has to say. Will check back and also let you know if my problem continues after cleaning that hose.

Aug 8, 2005, 03:08 PM
I have the same problem with water coming through the furnace.

I bought my house 1.5 years ago and last summer I discover this problem. Used a Home Warranty to get somebody to fix the leak and they said the problem was a problem with cleanliness. The drain was plugged. Tech blew compressed air through the drain pipe and fixed the problem.

Until this summer. Again water is dripping through my 15+ year old Lenox furnace (just had to replace fan and motor again home warranty paid for it) onto the newly repaired fan and motor.

I looked in the Tray or the condenser coils and apart from some rust there does not seem to be any sludge in the tray. I am unable to see the opening of the drain.

I fixed the problem for now by tapping on the one of the many bends in the PVC drain pipe with a screw driver and it started to drain properly.

The drain comes out of the furnace and there is a 90 elbow, the PVC drops 3 inches strait down, another 90 degree elbow turns the pipe to the left for 1.5 inches, then another elbow sending the drain straight up 2.5 inches, with another elbow sending the PVC to the left again for 3 inches before a final elbow sends the water on a angle into the catch basin (mounted on the fresh air intake) and pump to be sent over head to the laundry tub.

Is there any need for all these bends?

Aug 8, 2005, 04:31 PM
NO! Last summer I was working on an air conditioner at my church that several people had worked on before, and it was still destroying the ceiling below it. I came straight out of the pan with a 3/4'' nipple. I then clamped some 1'' ID flexible tubing over it and went over a couple of feet and then down into 15'-20' of 3/4'' PVC. The PVC does have a couple of elbows on the lower end, but there should be enough head to prevent clogs.

I see too many A/C drains that use small pipe, elbows everywhere, and are a pain to keep working. I suggest you start over again, use at least 3/4'' pipe, and as few elbows as possible. The sooner you get some drop, the better, water runs down hill. If you must jog over, use 45's if you can. The shorter and straighter the run, the less likely to clog.

Jul 9, 2007, 06:43 PM
I had this issue a month or so ago. Check the drain pipe from the furance (that drains moisture from the evap coil). In older systems, the drain pipe is a clear plastic hose that flows into a grate. Pull this plastic tube off the connector to the furance and clear out the build up with a screwdriver. If this is your problem, water will flow out immediately.

Oct 30, 2011, 01:11 PM
I had same issue. Last week my girlfriend went to do laundry and saw some water near the furnace/water heater so I looked at it when I got home.It appeared to be only a small amount on the floor like a cup of water, so I figured since we are new to the home buying thing... it may be normal.Today she did Landry again and saw it was leaking into the drain in the other room. After inspecting everything and looking on this forum and looking at my furnace... I did not understand why the humidification pump was not connected to my furnace in any way shape or form... I saw where it should have been connected and where it was no longer connected and that is where the furnace was leaking. So I took the cover off to find a mouse int eh base of the furnace in the corner closest to the drain tube. I assume the mouse somehow fell down the vents and could not get back up so it found its way into the base of the furnace. My cat must have herd it in there and been trying to get at it and disconnected the tube adapter thing that was on my tubing :-) Problem fixed. 24 Male Wisconsin -GL guys- Ondas