Please see the photo of the air handler copper pipes as my profile picture.
I tried attaching/uploading photos but was not able to. (For some reason the Manage Attachments link on the page did not work for me, even tried two different browsers)
What is the best way to repair an Air Handler's Heating Coil water leak, on and around the copper pipes?
The copper pipes run hot water only. I turned off the water valve over the summer, and the leaking stopped.

I would like to repair it before the winter starts. I know replacing the unit is an option but I prefer to try and fix it and get more use out of the unit before resorting to a replacement. The leak is not terrible but I know that any small leak is no good.
Thanks.

Can't see anything in your avatar, too small. When enlarged it becomes too distorted. Try posting picture again. Convert to JPEG format. There is a size limitation, converting to JPEG usually overcomes that problem. If not begin reducing the size of the picture.
Sounds like problem can be solved by resoldering joint.

I have something similar to this (heat coil image) http://ivany.net/wp-content/uploads/2008/01/p1010730.jpg
And the water started dripping towards the bottom of the unit. I stripped off all the insulation panels and found that the copper was a bit green and the casing below it around was pretty rusted. I cleaned it off some and put some epoxy putty around the coils and the steel cabinetry (where the coils come out from) but the water leak still persisted. I realized that I did a poor job cleaning the metal cabinetry as it still has rust spots and the expoxy did not adhere well to it.
What is the best way to clean all the rust off? But I'm afraid that the metal is more coroded than just rusty (and this is just at the bottom portion of the unit; like a square inch or two). -Maybe I can apply some sort of paint. Then... I should also braze the copper pipes around the areas where I suspect the leak to be? Yes? What is the best way to braze this type of coil? I have a propane torch, lead soder, and basic plumbing skills.
I believe the leak must be where the copper meets the metal. It's a very small flow of water that makes its way down to a small drip. Thanks!

Not being able to see the problem I have a difficulty advising but it sounds like the best thing to do about the pan or sheet metal is to clean good with wire brush, cut a piece of galvanized sheet metal (or aluminum) large enough to cover that area, coat the area with silicone, embed the patch material in the silicone and the rivet the patch material in place. Apply another coat of silicone.

To patch the copper pipe you will have to first find the leak. It is most likely at a joint. I could be where the tubing and the sheet metal come into contact with each other. Vibration wearing a hole in the tubing. Assuming the leak is at a joint you will have to determine if it is soldered or braised. Drain all water out of the system. Reheat the joint with your propane torch. If you can get the solder to run (melt) you have soft soldered joints. If you cannot melt the existing solder you probably have braised or hard solder joints. You will need a Turbo head and acetylene torch to hard solder.

Assuming you have soft solder joints, reheating the joint and adding a little solder may seal the leak. Probably won't. You will then have to heat the fitting and remove it. Wipe tubing with wet cloth while still hot to remove as much old solder as possible from ends of tubing. Sand solder on end of tubing until new fitting will easily slip on. Flux and solder new fitting in place.

To remove fitting you may have to cut tubing between joints then reconnect with a slip coupling.

If leak in in tubing itself, cut tubing at leak then reconnect with slip coupling.

I uploaded some photos to Flickr. They are all on this account. Here is the first photo (in link below), that shows a bit of water that trickles down.
http://www.flickr.com/photos/54882445@N06/5082944812
I believe the problem is here "where the tubing and the sheet metal come into contact with each other." I do not see any joints.
I cleaned up the area already. And the water has been shut off for at least two months but I believe there is still some water in the system since I still see some water, not enough for a constant drip but water is still present. This can prevent the solder from sticking, right?
Can I just try and put solder all around this copper, and close enough to the galvanized sheet metal, and that may do the trick? Any suggestions?

I have been away.
Put curser on picture, right click, choose "Save Image as". Open file with Paint. Draw circle where leak is occurring.
Post your response, click "Go Advance", scroll down and click on Manage Attachments, browse to find file, click "Open", then click "Up Load".

Pipes must be empty of all water. It is not that the water will keep the solder from sticking. It is that any water in the pipes will take the heat away faster than you can supply it, therefore you can not get the pipe hot enough to solder.

Cannot tell from picture whether this is hard solder of soft. Looks like soft. You will have to get all the water out of the pipes and apply heat to a solder joint to see if you can melt it.

Thanks! I am having trouble with this AskMeHelpDesk.com application. I cannot find how to post and upload photos. (I've done it in the past). I found a "Manage" button w/ "Edit" and "update" question options. None work, on Firefox or Explorer. It must be a bug/problem with this Question/Post?

-I do not know of a valve by the air handler equipment to drain the water out. Maybe closer to where it reaches the boiler? I'll figure it out.
-Here is an updated photo on Flickr) with the markings. Indicating were the leak is coming from.
http://www.flickr.com/photos/54882445@N06/5098686016/
The leak must be from corroded copper where the copper meets the sheet metal (that is rusty now). I don't think water is coming from any joints. If there is a joint there, it's maybe 1/2 inch away from the sheet metal. And the water appears as it's coming out exactly at the point the sheet metal touches the copper.

Cut away sheet metal and sand pipe so you can see exactly where the leak is. It will probably be a pin hole leak caused buy vibration of the sheet metal rubbing against the pipe.

If so you may be able to seal by soldering. However, here is what I would do.
Find an old electrical extension cord. Strip back an inch of two of insulation. Solder the end of the strands together. Remove about a two or three feet of insulation, twist the strands and solder the other end to keep the strands from unraveling. You want to use the stranded copper wire because it is soft and easy to bend and shape. Solder one end of the stranded wire to the pipe about 1/2 inch to one side of the leak. Allow the pipe to cool. Then wrap the wire around the pipe covering the pipe to about 1/2 inch to the other side of the leak. Push wraps of wire tight against each other and tight around the pipe. Flux and coat the wire with solder.
Solder, when hot is liquid. If you just solder, I think you will have difficulty getting any build up unless the leak is on top of the pipe. By wrapping the pipe with the wire you will give the solder surfaces to run in between.

Thank you! This sounds good! I will try this in a few days. I didn't get a chance to do it this weekend. I will report back how it went...

HKSTROUD --Your suggestion of cutting back the sheet metal and all were excellent. -I never thought that far, and not being familiar with the equipment didn't help much either. Your suggestion made sense so I went for it, and fixed the problem -the leak, but not before it got worst :-) The sheet metal was difficult to cut, it must have been 20 times stronger/thicker than the copper pipes I wanted to repair. During one of my angled cuts of the sheet metal with the electric saw, I went through most of one of the copper pipes... shhhzzz in split seconds! Sliced! So not only I had to repair two or three pin holes but a cut pipe as well. Additionally, even though the water was closed, I still had water running through the pipes and the solder wouldn't stick. I used a wet vacuum to suck the water out, and still that wasn't working as much. I ended up drilling additional holes on the lowest points of two pipes to finally drain all the water out. Then I knew if all my soldering wasn't good, I was going to likely drill holes again for draining the water (absurd!. ) Anyhow... despite another couple of challenges I managed. The soldering looks very very messy but that's the least of my worries since it's all going to be covered up. It's been a couple of weeks now and no water has leaked, so I'll be sealing it back up with pieces of sheet metal soon. Thank you very much for all your help! :-)