How to Repair a Leaking Hot Water Radiator

A leaking hot water radiator is not only inefficiently heating your home, but it could cause serious water damage. Although a leak in your hot water radiator is an indication that you will soon have to replace the radiator, you can make a quick patch that will stop any further leaks and extend the useful life of your heater.

Step 1: Shut off the water valve that was servicing the hot water radiator as soon as possible. Place a bucket or pan underneath any drips. Turn off the electricity to the hot water radiator as well from the main circuit breaker. Wait an hour to allow the water within the radiator to cool before attempting any repairs.

Step 2: Find the radiator drain valve and loosen it slightly with a bucket underneath to catch any water. Drain the radiator completely, opening the bleed screw at the top of the radiator for even faster drainage. Watch the bucket while draining the radiator and empty it as necessary.

Step 3: Continue allowing the radiator to drain until there are no more leaks. Empty the bucket a final time and move it out of the way.

Step 4: If the leak is near the lockshield valve, remove the lockshield valve. First look for a screw that will be holding the cap onto the lockshield valve. Loosen and remove this screw, you should then be able to remove the shield.

Step 5: With the valve exposed, use pliers to grasp the valve firmly while using another set of pliers to turn the coupling that is located in the middle of the lockshield valve and radiator.

Step 6: With the threads of the coupling exposed, use this opportunity to add more pipe thread compound to the threads. Screw the coupling back together using both sets of pliers.

Step 7: If the leak is simply a hole within the radiator itself, you can use a welding solvent to patch the leak. In this case, use a wire brush to clean the area thoroughly and lightly sand around the hole. Mix the welding solvent according to the directions of the manufacturer, then press the welding solvent into place to seal the hole. Wait 6 hours, or the length of time recommended by the manufacturer to allow the welding solvent a chance to cure. Then you can reconnect the water and electricity to the radiator.

TIP: A patch to the actual body of the radiator indicates that it will soon need to be replaced. Plan on shopping for a new heating system as soon as possible: you should not expect the patch to hold for more than one month.