If your home uses hydronic baseboard heating and you discover a large wet spot in your carpeting near the wall, it is likely that the baseboard hot water pipe is leaking. Leaks in the soft copper pipe are common, especially if you have turned off the system for an extended period of time during cold weather. Freezing water can burst pipes and make a big mess as a result. Fortunately, repairing the system is a task that many homeowners can handle. Below is how you should respond to a leaking hydronic baseboard heater and perform a repair of the damaged pipe:
Tools and materials you will need
Section of copper pipe - choose the exact diameter that matches your baseboard heater water supply
Slip coupler - this part consists of a short copper tube designed to fit snugly around the copper pipe. A slip coupler can be purchased with an internal stop to help align the pipe ends, but the repair is made easier by using a stop-less coupler. A coupler without a stop is able to be moved along the pipe ends with a high degree of flexibility.
Drain coupler - constructed of brass, the drain coupler has a small nipple and cap that permits water to drain from the pipe. It also slips over the pipe ends and can be adjusted as needed.
Plumber's sanding cloth - this tape-like material consists of a flexible fabric backing with embedded grit. Purchase a cloth that contains 120-grit aluminum oxide for best results.
Plumbing soldering flux - purchase a flux that is specifically designed for plumbing applications.
Plumbing solder - be sure not to purchase electrical solder, as plumbing solder contains an acid that helps clean the metal and strengthen the joint after soldering.
Multitool with metal-cutting blade or hacksaw
Adjustable locking pliers
1. Turn off the supply line at the boiler - As soon as you discover a possible leak, be sure to immediately turn off the boiler supply line. Low levels of water are a cause of boiler failure, and you must stop the leaking to prevent devastating accidents or damage.
2. Access the leaking pipe - Once the boiler water supply is shut off, you can safely access the leaking pipe to perform a repair. Remove the baseboard covers that protect the pipe and set them aside in a safe location. This will expose the interior copper pipe as well as heating fins that line the pipe. Search along the edge of the pipe to determine where the leak is, and mark off a couple of inches along either side of the pipe to serve as a cutting guide.
3. Remove the bad section of pipe - To remove the copper pipe, cut along the lines with either a multitool or a hacksaw if you have the room to maneuver in the limited space. Pull the section of bad pipe out of the baseboard heater.
4. Prepare the ends of the pipe - After the leaky section of pipe has been removed and thrown away, the next important step is to sand the outer edges of the pipe ends with plumbing sandpaper. This step will remove burs and roughen the exterior surfaces of the pipe ends;
5. Cut the new piece of pipe - Hold up the section of the copper pipe to the gap where you removed the leaky piece. Use a marker to indicate where the pipe needs to be cut in half, so it will fit in the gap; next, cut the pipe with the multitool or hacksaw.
6. Attach the new piece of pipe - Apply a plumbing soldering flux to the outside edges of the new section of pipe and the pipe ends. Next, slide the coupler onto the pipe end. At the other end of the pipe section, you need to slide the drain coupler on over the flux.
While maintaining a grip on the pipe section, slip the ends of each coupling over the existing ends of the pipe. Be sure to rotate the drain coupling so its nipple is pointed toward the floor. If you have difficulty slipping the couplers over the pipe ends, use a pair of adjustable pliers to provide leverage and move the couplers. Leave the cap off the nipple to permit steam from residual water in the system to evaporate.
7. Solder the connection - The last step is to solder together the connections. Heat the couplers at each end with a propane torch, then touch the tip of plumbing solder to the hot joints between the slip coupler and pipe. This will cause the solder to be "sucked" into the joints. Visually check to be sure the solder is being absorbed into the seams and is not simply melting and dripping. If everything looks acceptable, then allow the solder to harden and check the water flow from your furnace to be sure it isn't leaking.
If you have trouble with any of these instructions, contact a contractor from a company like SDA Armstrong Mechanical Services Ltd for assistance.