How to Replace Galvanized Iron Pipe and Fittings Part 3 How to Replace Galvanized Iron Pipe and Fittings Part 3
In the first and second parts of this guide to replacing a galvanized iron pipe, you learned how to remove the old pipe, and how to cut the new pipe and add suitable attachments. In this third part of the pipe, you will need to know how to join the second threaded pipe to the fitting, and then how to add a union fitting to the pipe. Fitting all the pieces together should not be too difficult, but you will need to have some basic home improvement knowledge, and also be able to follow this guide so that you can get all of the parts fitted together.
Step 1 - Clean the Pipes
Now you are ready to attach the new pipe to the remaining galvanized iron pipe, you should begin to clean out the threads. Remove old dirt and debris from the old pipe by using a small wire brush. The brush should be slightly bigger than the hole in the pipe, and you should take care not to bend down while you are scrubbing the threads. Turn the brush clockwise in order to get the bristles deeply into the threads.
Step 2 - Add the Threaded Pipe
Once you are ready to join the pipes together, you can add a layer of joint cement to the pipe, and simply screw them in together. There are two reasons why you might want to avoid this direct approach to the matter of adding a new pipe. Firstly, the pipe may not be of exactly the same metal composition, in which case you could find yourself building a large battery, complete with circuit. Also, the threads on the old pipe might not be good enough to hold the new pipe. A better alternative is to add a fitting.
Step 3 - Add a Union Fitting
One of the best ways of uniting differently aged metals is to use a union or pipe nipple fitting. These will allow the two pipes to be held together by the union, but they will keep the pipes away from each other, so that there is no risk of a current being formed. Take the pipe nipple, and add a layer of joint cement to the part. With this done, screw it into the original fitting, using a wrench to tighten it fully. Apply the pipe wrench to the nipple, and then slowly join the new pipe to the nipple and screw together. Tighten both of the united pipes with the wrenches.
Step 4 - Test the Pipes
Once you have done this, you should be ready to turn the water back on. Don't use the full pressure to start with but test that the pipes can carry the water through the water system without leaking. Check for water patches, and dampness, particularly around the union joins. If there is no sign of leaking, you can use the pipes as usual.