Hardware And Plumbing How To Install A Natural Gas Water Heater

Installing a gas water heater is possible for a homeowner if they follow the directions for the installation.

Installing a gas hot water heater often begins with removing the existing one. To begin this procedure, shut off the water supply to the water heater. This can be done at two different places. Cold water enters the water heater on the top, right side of the heater through piping. This piping should have a valve that can be shut off, located on it before it enters the water heater. If there is no valve located on the cold water piping entering the water heater, the water supply for the entire home will have to be shut off. After shutting off the water, begin draining the water heater by opening the hot water spigots. Now it is time to shut the gas off going to the water heater. The gas line should have a gas valve located on it that goes to the heater, simply shut it. If there is no valve, trace the line until one is found and shut it off. With the water and the gas shut off, it is time to continue removing the water heater.

Located on the top of the water heater is a smoke pipe, called flue piping. Remove it from the heater; removing it from the chimney is not necessary. Now use a 14-inch and an 18-inch pipe wrench and loosen the ½-inch union located on the gas connection at the water heater. Remove the ½-inch piping that goes into the water heater to use on the new water heater. The next step is to loosen the two ¾-inch unions located on top of the water heater. If the hot water heater has no unions, simply cut the pipes about six inches from the top.

Now the water heater is ready to drain completely. Open the drain valve located at the bottom of the water heater if a floor drain is nearby. Two buckets, used alternately by draining and refilling them will drain the tank if there is no floor drain. Sometimes emptying the tank is accomplished by using a garden hose attached to the drain and run outside.

While the tank is emptying or after it has completely emptied, remove the pipes for the hot and cold water. Reusing these pipes on the new water heater is possible if they are still in good shape. Inspect all valves and piping coming in or going out from the water heater at this time and replace any that are not in good shape.

After the tank has completely emptied, remove the old water heater. The removal is usually a job for two people as water heaters can be heavy even when empty. Now the new water heater can be set in place and the installation can begin.

If the new water heater is the same size as the old water heater, the piping should be the same and line up with no problems. Be sure to line up cold on cold and hot on hot. The cold water is usually the pipe on the right side and should have a valve on it. If it does not have a valve on it, one can be installed at this point. Other items to install now are a ¾-inch relief valve and a blow off tube. The relief valve should have a temperature sensor that goes into the water heater and should be installed using Teflon tape or pipe dope. Install the new blow off tube on the female threads of the relief valve, with the tube extended to within 6 inches of the floor. Make sure the floor end of the blow off tube has no thread, it is clear of any obstructions, and there is no reduction in size between the blow off tube and the relief valve.

At this point, it is time to reconnect the ¾-inch unions or to install new ones along with piping. Using a tape measure will ensure exact lengths when replacing the unions. Only use hard pipe, do not use flexible copper connectors. If galvanized steel piping is used in the house, use galvanized steel on the water heater also. Same with copper, if copper is used in the house, use copper on the water heater. Remember to use Teflon tape or pipe dope on galvanized steel.

Now all the piping should be connected to the water heater. Open the lowest hot water fixture in the house and turn on the cold water supply to the water heater. While the water heater tank is filling, check for leaks. Leave the fixture open until water begins to escape from it then shut it off. If no leaks were found it is time to move on to the next step.

The gas piping, which should be black, as well as fittings and ½-inch union will be reused. Do not use flexible connectors. If there is a difference in the height, install enough nipples to make up the difference. Remember to use plumber's pipe dope on all connections.

The draft diverter, which is a steel piece that goes on top of the water heater and is what the carbon monoxide vents through, is installed now. If the old flue pipe can be reused, after inspecting it, reinstall it with the piping pitching upward a minimum of ¼-inch per foot for proper venting. This prevents carbon monoxide from spilling. The flue piping must be properly cemented into the chimney.

Now it is time to get ready to light the pilot on the water heater. Double-check the gas and flue piping. Gas leaks can be found by mixing and applying a dish soap and water solution and applying it to the gas piping. If bubbles form, there is a leak; if there are no bubbles, there is no leak. Now the plates to the burner can be opened and the gas valve turned on.

The water heater control has two knobs on it. The knob on the front will be on vacation or the lowest setting. The knob on the top has three settings, which are on, off and pilot. Turn this knob to pilot. Now depress the knob and hold it for three to five minutes, this gives the gas time to get to the pilot. Light the pilot with a lit match inside the heater. If the pilot will not light, keep depressing the knob until the gas has reached the area and the pilot is lit. Once it is lit, remove the match but continue to depress the knob for another three minutes. This step allows the thermocouple to heat up. Release the knob now. If the pilot goes out, repeat the procedure above. If the pilot stays lit, close the compartment plate.

After the pilot stays lit and the compartment plate is back in place, turn the top knob to the ON position. The front knob is now turned to the medium position and the water heater should fire up. If it does not fire up the pilot light may have gone out and will have to be relit. After the water heater fires up, the comfort level of the water can be adjusted by setting the front knob to the desired position.

Give the water heater time to warm the water to the desired temperature, then it will be ready to use.

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