New Gas Hot Water HeaterA gas hot water heater installation is needed when your old water heater has gone to a better place. Are you sure your water heater needs to be replaced? Have you checked on possibly fixing it? Water heaters can last ten to fifteen years. Is yours older than that? Installing a new gas water heater is a big job for a homeowner. Yes it can be done in a day if things go well.

Before you decide on a new gas hot water heater installation you want to make sure you can't repair the one you have. See the article Gas Hot Water Heater Troubleshooting for things you can check on.

This article covers the installation of a standard, normal draft gas hot water heater. These are the lowest cost to purchase and the easiest to install. On demand, high efficiency or induced draft units are not covered in this article. Feel like you are in the right place? Then read on.

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What Can You Save?

A standard 40 gallon gas hot water heater installation should run between $800 and $1,000. Size matters and so does the age of your current installation. An installer may tell you need other parts and this will drive the cost up. Sometimes another $200 to $500 of up selling can take place.

How Hard Could It Be?

A gas hot water heater installation is a fairly difficult job and will take most of a day if all goes well.

These repairs will have a Difficulty Level of: Difficult
These repairs require a Skill Level of: Determined Handyman

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Check the Simple Things!

There is nothing simple about installing a new water heater. Check out the article Gas Hot Water Heater Troubleshooting, to make sure the water heater is really a goner.

What Can Go Wrong?

gas hot water heater installation pic5A gas hot water heater installation is a big job. It involves natural gas and gas can explode. Make sure the gas is off and the area is well ventilated. The water in your tank will be hot if the heater is working. Cool it down before you try and drain it. Size does matter, and getting a water heater that is a different size that the one you had will require that the hook ups be modified. Not getting the job done will leave you without hot water. Not a savory thought.

Selecting a New Hot Water Heater

Gas hot water heaters come in different sizes. Getting one with that is the same height will make a huge differences on how hard the hook ups are going to be. There are some key dimensions. One is the height of the top of the water tank from the floor. The second would be the height of the gas supply line from the floor. It is not the end of the world if you can't find an exact match. It just means that you will have to modify the piping. Another consideration would be the vent pipe. Most water heaters have 3" vent pipe. You cannot reduce the vent pipe so getting a new heater with a larger vent is a problem.

The next concern is the cost. Gas hot water heaters can range in cost from around $300 on up to $2,000 for a high efficiency model. In this article we will make the assumption that you are going for a less expensive standard model. These should be in the $300 to $600 range.

Watch where you buy your hot water tank. Some online vendors and specialty stores have disclaimers that void the warranty if you install the hot water heater yourself. The home supply stores that cater to do it yourself customers, have warranties without this disclaimer. Obviously they exclude improper installation and incorrect usage.

Water heaters are a big item and will not fit in the trunk of a car. In addition they are glass lined and should be handled with caution.

Some ancillary items that you might need would be: (1) Dielectric unions or nipples. Some water tanks come with these installed. You will have to check with your building department to find out if these are required. (2) Pressure relief valve. Some new water heaters have them pre-installed, others do not. A drip pan, these are suggested and required in some places. A stand if the water heater is going in the garage. The bottom of the water heater needs to be 18" off the ground in a garage. You may also need misc. fittings to make the connections.

WARNING!! Natural Gas Can Explode! Make Sure the Gas Is OFF!!! The Hot Water Can Be VERY HOT!!! WARNING!!!

Removing the Old Water Heater.

Removing your old hot water heater is part of a gas hot water heater installation. The first thing you want to do is turn off the gas to the water heater. You should have a shut off valve in the gas line near the connection to the gas valve. You turn the valve ninety degrees until it is perpendicular to the gas line. Next run some hot water in a sink nearby until the water cools down (if the water heater is not working you can skip this step).

Shut off the cold water inlet valve and leave the hot water faucet open in sink nearby. Hook a garden hose up to the drain valve near the bottom of the tank. Run the hose to a floor drain or outside and open the valve. After it has drained down a little way, you can open the pressure relief valve and shut off the faucet.

At this point you can unhook the gas line. You should have a union below the shut off valve. Use pipe wrenches to loosen it. You want to hang onto the nipples and fittings that are connected to the hot water tank. Remove and save everything up to the gas valve.

Next would be the water lines. The cold water inlet and the hot water outlet. Again you should have unions not to far above the tank. Loosen the unions with two pipe wrenches. Unhook the first section of vent pipe from the fume hood and the first fitting. Save this piece also. At this point the tank should be free.

You should remove the fittings and nipples at the top of the tank as long as they are in good condition. One more item you will want to salvage is the drain tube that extends down from the pressure relief valve.

This is where you need the helper. Get some help to remove the old tank. Disposing of it might be a chore in itself. For now you want to get it out of the way.

Placing the New Water Tank

The next step in a gas hot water heater installation is unpacking the new unit. It is best to do this out away from the area it is being installed. There should be some instructions that come with it. Read through the instructions and look for any special items that need to be attended to. Be aware of any temporary plugs or shipping braces that need to be removed.

Are you installing a drip pan. Put in place before you try to set the water tank. Using some help again carry the new water tank into the location and set it in position. Turn the tank so that it is oriented the same as the old one. The hot and cold water lines and the gas line all need to line up.

At this point you find out how much trouble you are going to have with the fittings. Try dry fitting the gas line parts from the old water tank. Do they line up? Yes, great, this is good news. No, Take some measurements. Remember to allow 3/8" to 1/2" of additional length for each threaded end. You might want to make a sketch of what you will need.

Now check out the water line nipples. Are adjustments needed. For a tank that has dielectric nipples installed you will need a coupler and possibly a reducer. The nipple length may be off. Measure from the inlet and outlet on the water tank up to the bottom of the union. Make yourself a little sketch with the dimensions. You may have flexible connections here. Some building departments allow it. If you do that is a lot easier.

Mark your sketch with the fitting types, male, female and union and to what point on the fitting you are measuring to. Oh, almost forgot, size of pipe, either 1/2" or 3/4" or a combination of the two. I know this is a little tedious, but it is a necessary step in a gas hot water heater installation.

Last you want to put the new fume hood in place on top of the tank. How does your vent pipe line up. Is the old piece long enough and the right size? Yes? Good news. No, then you will have to get another piece of vent pipe.

Are you ready for a trip to the supply house? Take your sketches with you and go to a home supply store that does pipe threading and has a plumbing department. Ask for help and explain your situation. They should be able to cut and thread the pipe for a nominal sum. In addition they can get you the right fittings to make the connections. Get some suitable joint compound while you are there.

Installing the Gas Line

With the right fittings in hand this step of your gas hot water heater installation should not be hard at all. You use pipe wrenches to tighten gas line. You want to use a joint compound on the threads that is suitable for gas connections. Start with the nipple going into the gas valve. Remove the plastic cap first. Tighten the fitting snug. Put the tee on next and then the upper and lower nipples. The lower nipple should have a cap on it. The upper nipple goes into the union.

Make sure all the connections are tight and then tighten the union. Turn the knob on the gas valve to off. You can turn the gas on at this point. Use soapy water to check for leaks. Never use an open flame to check for gas leaks. Find a leak, you know the drill, take it apart and tighten it.

Hooking up the Water Lines

Water line hook up in a gas hot water heater installation is e lot easier when you have the right fittings. Again you should use pipe joint compound on the threaded connections. Be sure to remove the plastic caps. Work from the water tank up toward the unions when tightening things. Make sure the connections are tight. Hook up the unions and that should be it.

Then last item would be the pressure relief valve. Again use some pipe joint compound on the threaded connections. Tighten the relief valve with the outlet turned down. Install the outlet tube that you took off the old unit.

Hooking Up the Vent

Did you listen and get a water heater with the same size vent? Good, your gas hot water heater installation is a lot simpler! You will have to replace all the vent pipe up to the chimney if you got one with a larger diameter.

Install the fume hood on then top of the tank. The fume hood should set level and the legs should be straight. There should be some holes for the legs. Get the legs in place and hold down on the fume hood. You want to run some sheet metal screws down into the holes next to the tabs on the legs.

Cut your vent pipe to length, remembering the parts that slip over. Screw the vent pipe into place using sheet metal screws.


Starting it Up

You have to fill the hot water tank before you can turn on the burner. Open a hot water faucet nearby and turn on the water. Let the tank fill until all of the air is bled out of the tank.

Check for leaks and tighten anything that is leaking. Read the instructions for lighting the pilot. Every water heater varies slightly on this procedure. With the pilot lit you should be able to turn the gas valve to on and the heating process will begin. A hot shower is not too far in the future.

Gas Hot Water Heater Installation Summary

Now that was a big job. You might be a little tired, but you likely saved $300 to $500 doing the work yourself. Was it worth it? You will have to be the judge of that. I have heard horror stories of homeowners that were sold hundreds of dollars of additional parts when the plumber came out to actually install the heater. You may have saved even more.

With this experience under your belt you are ready to tackle just about any home repair project. What will you do now? For today a little rest is in order. Tomorrow, who knows.

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