How to Repair a Broken Furnace Shut Off Valve

Man repairing a furnace
  • 2-3 hours
  • Intermediate
  • 50
What You'll Need
New shut off valve
Pipe cutter
Emery cloth
Propane torch

A broken furnace shut off valve is a serious problem that must be attended to as soon as it is realized. The shut off valve stands in between the oil supply and the actual furnace itself. In order to ensure safety when working on other parts of the furnace, the shut off valve stops the flow of oil, hot water, or other type of material that the furnace uses to create the heat. Repairing a broken shut off valve is an easy process, but does require some close attention to detail.

Step 1 - Determine Size of Shut Off Valve

Before you start to cut open the pipes of the supply line to your furnace, you will need to make sure you have the right sized valve to replace the old one with.

Step 2 - Shut Off Supply

Repairman working on a furnace

In many instances, the supply line will have a main shut off that will stop the flow of oil, gas, or other material. Shut this off before doing any type of work to the shut off valve that requires repair or replacement.

Step 3 - Cut Off Valve

Place a bucket, or some other container, to catch the fluids left in the line. Use pipe cutters and cut off the valve as close to the valve as possible. If you are not sure about the size or the type of shut off valve that you needed, now is a good time to take the valve into the hardware store to compare.

Step 4 - Sand Ends of Pipe

Use the emery cloth to clean off the ends of the pipe that was cut. Clean off the ends of the new valve before you place it on the line. Any type of contaminant from dust, residue, or other dirt has the potential to ruin the seal or damage the furnace.

Step 5 - Set Shut Off Valve in Line

After the ends of the pipes are sanded off and clean, set the shut off valve into the line. Push the ends of the pipe into the valve as far they will go. This is to make sure that the valve will fit. Remove the shut off valve and apply some flux around the outside of the pipes. Install the pipes into the valve again.

Step 6 - Solder Pipes Together

soldering a copper pipe

Turn on the propane torch and apply heat to the junction of the shut-off valve and the supply pipe. After a few seconds, touch the end of the solder to the pipe. When it is hot enough, the solder will melt and wrap around the junction making a seal. Repeat this process with the other end of the valve.

Step 7 - Turn on Main Valve

After the shut-off valve has been installed, go to the main and turn it back on. Turn it on slowly in the event that the shut-off valve will have a leak in it. Once the valve is open all the way, turn on the new shut-off valve. If the shut-off valve is not leaking, you are able to turn the furnace on for heat.