How to Replace Your Gas Water Heater

Step.1 Determine if you are capable to do this job safely. This project is going to involve you in being able to identify, shut off, disconnect, and reconnect both water and gas or propane piping. If you are not sure about this at this point then is the only step you need except calling a plumber.

Step. 2 OK you have determined that you are not going to blow up your house doing this project. The next step is to select and purchase a new water heater. The best advice I can give on this is to get the gallon size that you think you will need and also know whether you have a natural gas heater or a propane one. I think most families can do just fine on a 40 gallon model but if you have large hot water needs such as a large Jacuzzi to fill up you may want to look into getting a larger one. A little research may be needed here to determine the needs of the specialty tub.

Step 3. Disconnect gas supply. The absolute best way to do this is directly outside at the meter for natural gas and at the tank for those who have propane models. It is possible to only shut off the gas cock that is directly upstream of the water heater’s gas valve but if you make an error as novices do you will be very glad you took the additional safety precaution. Once you know that the gas is off and verify that the pilot burner has gone out, it is now time to loosen the union on the piping and remove the pipe nipples that go into the gas valve. Set these pieces aside because they almost always will fit the next water heater that you have purchased.

Step 4. Shut off water supply and break vacuum. The water supply should be shut off above the tank using the valve there and also at the water meter or well pump inlet. Once the water is off open both hot and cold faucets on different level of the house. This allows the vacuum that builds up to be relieved as the water drains out of the piping. This also speeds up to process of draining the water from the lines which will soon become the enemy once it is time to solder.

Step 5 Drain tank. Have a section of garden hose ready that can reach a floor drain or to the outdoors if you have a slab home. Open the valve and be careful if it is a plastic valve because they have been known to break off and cause a big mess. Now look up from the drain valve at the bottom of the tank to a brass fitting that is poking out of the side of the tank. This is your pressure relief valve and if you grasp the metal handle and pull it out you will drain that tank much quicker because this also helps break the vacuum of draining water.

Step 6 Once the tank is empty or empty enough to haul it away safely it is time to cut the pipes coming into the tank. Copper pipes will require a tubing cutter to be used and PVC can be cut with a hack saw. I do not recommend do it yourself installations for water heaters that have old steel piping because even the pros have problems with this. Cut the cold line at least 2 inches below the valve that you used to stop the water flow. The hot water line could be cut higher but you might as well have the new joint uniform.

Step 7. Remove sheet metal vent pipe from the chimney. This is another item to hold on to if it is still in good shape because even though thirty years have passed since your water heater was installed not much has change on the new model. The best way to see if you vent is still good is to squeeze it firmly to see if your fingers push through the wall or if it starts to come apart.

Step 8 Discard the old heater. The neighborhood that I used to live in was patrolled daily by scrap haulers. Some of them have ads in the local papers and pick up for free.

Step 9 Set the new tank into place. Put the new unit exactly where the old unit was once sitting. The gas piping, vent and water piping will line up well it.

Step 10 Reconnect water piping. I always do this first because once you get the water hooked back up you can start to fill the tank while you finish the other parts of the installation.

Step 11. Fill tank and check for leaks. You might be asking yourself why I didn’t explain how to solder the pipes or reconnect plastic piping I will write about that another time because it can be somewhat involved. If you have leaks now is the time to find them and not when everything is hooked up and making adjustments is more difficult.

Step 12 Reconnect venting. You may be able to reuse the old venting if things line up correctly but if not new venting can be purchased and installed to fit the new unit.

Step 13. Reconnect the gas piping. Now you are glad that the junk man didn’t get those pipe nipples you saved. Hey, it saved you a trip to Lowes.

Step 14. Check for gas leaks. I personally use a lighter to find any small gas leaks on the piping that I have installed. Most people are afraid to do this but the gas will light at the leak source and burn like a tiny pilot light until you blow it out. If this bothers you as it should just mix dish soap and water in a spray bottle and apply to piping. If you have a leak it will bubble.

Step 15 Light water heater pilot light. All new tanks have a spark igniter which is similar to those found on a gas grill. Follow lighting direction closely and keep in mind that you just had the gas piping open and it will take a bit of time to push that non combustible air out of that tiny pilot orifice.

Tools needed; Pipe wrench, channel locks, straight tin snips, drill for sheet metal screws, water hose, pipe soldering kit and cutters or saw or cutter for PVC piping.