Installing Water Heaters
Even with proper maintenance, your water heater will eventually need to be replaced. Either a gas or electric water heater will supply your hot water needs efficiently. Choosing one over the other is a matter of what kind of service is available to your home and what makes the most economic sense.
PAY ATTENTION TO THE WARRANTY. Warranties vary in length. Six to 12 years on the tank is the usual life span. Check the limitations of different manufacturers’ warranties. The life of the water heater will depend on environmental factors; hard water shortens its life.
THE ENERGY FACTOR. Water heaters bear a yellow Energy Guide sticker that shows yearly usage for electricity and natural gas. Rate of recovery is not listed on the tag, but ask about it. It reports how quickly the unit heats the water.
SIZE MATTERS—ELECTRICITY. A family of up to four in a home with two full bathrooms, a washing machine, and a dishwasher should have a 50- to 80-gallon tank with a 5,500-watt heating element. A family of five with the same appliances should have a 65- to 80-gallon tank and a 5,500-watt model.
SIZE MATTERS—GAS. A family of up to four in a home with two full bathrooms, a washing machine, and a dishwasher needs a 50-gallon tank with a 40,000-Btu burner unit. A family of six with the same appliances needs a 50- to 75-gallon tank and a 40,000-Btu model. A family of up to seven needs a 50- to 75-gallon, high-input 52,500-Btu unit.
CARBON MONOXIDE IS DANGEROUS - Colorless and odorless, carbon monoxide causes about 10,000 injuries a year. Symptoms of gas poisoning include headaches, fatigue, and nausea. Install a carbon monoxide detector and have gas appliances inspected once a year.
THE TANKLESS STORY - Electric or gas tankless "on demand" water heaters have recently been introduced in North America. While more expensive, they are more efficient than conventional water heaters. The savings in energy and maintenance could make up the difference in cost. Tankless heaters save money because they don't need to heat a tank full of water. When you turn on the faucet, cold water flows through heating coils and is instantly heated to 105 to 115 degrees. When the faucet is turned off, the heating coils turn off as well. Check details with your local home center. Large tankless heaters may require professional installation. Smaller "on demand" heaters can be installed in remote locations.
Water Heater Installation Basics
MATERIALS: Electric water heater, acid-free flux, Teflon tape or pipe compound, wire nuts, water heater heat trap fittings, 2x4 support, plastic shims, matches or grill igniter, masking tape
TOOLS: Hacksaw or tubing cutter, wire brush, carpenter’s level, two adjustable wrenches, MAPP torch, screwdriver, rags
HEAVY WATER - Even empty water heaters are heavy and clumsy. Get the old heater out of the way first. If possible, leave the new heater in its box and slide it gently down the stairs. Stand it up and slide it to where it belongs before you cut off the box.
Installing a new water heater begins with the old heater. If you’ve got an electric heater, replace it with an electric heater, unless you’re willing and able to run gas line and exhaust vents. If you’ve got a gas heater, stick with gas, unless your breaker box has room for (and you’re willing to install) a new 240-volt circuit. Whether the heat source is gas or electricity, make sure you shut it off before beginning work. Electric heaters can be cut off at the breaker box and may have an additional breaker closer to the heater. Gas heaters will have a cut off valve, usually with a red handle, along the line leading to the hot water heater.
Water and electricity are a dangerous mix. The power should be the first thing turned off and the last thing turned on during the installation process.
1 REMOVE THE OLD WATER HEATER. Turn off the water and gas supply valves and the power. Remove the electrical supply access plate at the top of the water heater. Check the connections with a continuity tester to make sure the power is off. Attach a garden hose to the drain valve and empty the tank. Using two pipe wrenches, disconnect the gas line at the union fitting if the pipe is galvanized, or at the flare fitting if the gas supply line is copper.
2 DISCONNECT THE WATER LINES. Using two adjustable wrenches or pipe wrenches, disconnect the piping above the tank. If the piping has been soldered into place, use a tubing cutter to cut it.
3 SET THE NEW WATER HEATER. Install the water heater in an area where it won't be cramped. Leave at least 6 inches of clearance around it for ventilation. Don't set it next to flammables. Turn the water heater so that access to the burner and controls is unobstructed. Place a level on the side of the water heater and plumb it with plastic shims.
4 WRAP THE HEAT TRAP FITTING THREADS. Use Teflon tape on the pipe threads. These fittings are directional and must be installed properly. Both have arrows showing the correct direction for installation. Attach the blue-coded fitting to the cold water inlet with the arrow facing into the water heater. Attach the red fitting to the hot water outlet with the arrow pointing away from the water heater. Tighten using two pipe wrenches or adjustable pliers.
5 IF YOU REMOVED THE SHUTOFF VALVE, REPLACE IT. Sweat solder the shutoff valve to the end of the cold water supply pipe. Use a MAPP torch and lead-free solder to connect the valve to the supply line. Solder with the valve in the open position to avoid overheating the parts.
6 INSTALL THE WATER LINES AND PRESSURE RELIEF LINE. Use two adjustable wrenches to connect the pipe from the pipe run to the water heater. Turn the main shutoff on and open all line valves. Open all the faucets in the house and run the water until it flows steadily from them. Close the faucets.
Wiring An Electric Water Heater
DON’T BLOW OUT THOSE HEATING ELEMENTS - Heating elements for electric heaters are extremely fragile. You'll burn them out in an instant if you power up the heater before it is full of water. To prevent this:
• Open the heater's cold water supply valve so that water can flow into the heater.
• Open the hot water faucet in the bathtub.
• When water starts flowing into the bathtub, the heater is full. Close the faucet, and turn on the electricity.
1 REMOVE THE ELECTRICAL ACCESS PLATE. Always turn off the power to the unit before you do any electrical work. Connect the electrical supply according to the manufacturer's instructions using wire nuts. Connect the bare copper or ground wire to the ground screw. Replace the electrical access plate. Remove the thermostat access plate.
2 ADJUST THE THERMOSTAT. Recommended settings are 120 to 125 degrees. Now open a faucet near the heater, turn on the water supply, and fill the tank until the faucet is flowing. The tank must be full before you restore power. When the tank is full, restore power and press the reset button on the panel.
Gas Water Heater Installation
1 INSTALL THE FLUE HAT VENT LINE. Measure, cut, and assemble the vent pipe that runs from the flue hat to the roof vent stack. Make sure horizontal sections have a slope of 1/2 inch of rise for every foot of length to efficiently carry fumes away from the house.
2 ATTACH THE DUCTWORK. Connect the ductwork by driving 3/8 inch sheet metal screws into the vent every 3 to U inches around the duct. You will need at least three screws per joint.
3 CONNECT THE GAS SUPPLY LINE. Clean all threads with a wire brush and rag. Apply pipe compound to the threads of the galvanized pipes as you connect them. Assemble and tighten each fitting with two pipe wrenches. Install the union fitting last because it connects the new line to the existing line. Once finished, open the gas supply valve.
4 TEST THE GAS LINE FOR LEAKS. Fill a sponge with liquid dishwashing soap and water. Apply it to the new fitting and look for bubbles. (The same process is used for finding a leak in a car tire.) If a leak is present, bubbles will form on the surface and you'll have to refit the joint. Test all connections.
5 LIGHT THE PILOT. Use a fireplace match or a grill igniter to light the pilot. Replace the burner access panel and set the control at 120 to 125 degrees.
CHECKING FOR GAS LEAKS - Make sure the connections in your gas line are tight and that they don't leak any gas. Start by using plenty of pipe dope during assembly—it's cheap, and you can always wipe off the excess. When you turn the gas back on, check for leaks by brushing a 50-50 mixture of dishwashing soap and water on the joints. Leaks will show up quickly in the form of bubbles. Never test for leaks with a burning match. A small leak is enough to start a fire. A medium sized leak can put enough gas into the air to cause a small explosion. And you never know—the leak you discover could be a large one.
Installing An On-Demand Water Heater
MATERIALS: On-demand water heater, cutoff valves, solder, flux, Teflon tape, high-pressure flexible hose, cable, armored cable, junction box, cover and clamps, wire nuts, wire caps, electrician’s tape
TOOLS: Pipe cutter, propane torch, wrench, drill and bits, screwdriver, wire cutter, needle-nose pliers
VARIABLES: Make sure your breaker or fuse box has an extra circuit before starting. You'll need one free breaker for 120-volt heaters or two free breakers for 240-volt units. Time needed to run wire or pipe is not included in the estimate.
REQUIRED SKILLS: You will need basic carpentry, plumbing, and electrical skills.
Turn off the power before you begin.
An on-demand water heater can easily be mounted under a kitchen sink or off to the side, in places where looks don’t matter. When you turn the hot water tap on, the flow turns on a heating element that heats the water as it runs through copper tubes. When the faucet goes off, so does the heat. Because 20 percent of a home’s energy use goes into heating water, an on-demand unit can save a lot of money. To meet code, you will need a cutoff switch within sight of the unit, and cable must be flexible or housed in conduit.
1 RUN POWER FOR THE UNIT. It will be either a 120- or a 240-volt circuit, and it must be a circuit wholly devoted to the heater. Either voltage requires 8-gauge wire, and the section exposed to the area under the sink must be armored cable. If the manufacturer's instructions call for a larger cable, the National Electrical Code says you must comply.
2 IF YOU’RE INSTALLING THE HEATER UNDER AN EXISTING SINK, turn off the water and cut through the water line. Drain the line by opening a faucet at a lower point somewhere in the house. Solder a cutoff valve onto the pipe stub that comes from the floor or wall. Solder a second valve onto what's left of the line that runs to the faucet, cutting the line as necessary to allow room for the heater.
3 SCREW THE UNIT TO THE WALL, following the manufacturer’s directions. Connect the water supply line to the cold in-feed fitting with soldered copper pipe or high-pressure flex connections as shown here. Wrap Teflon tape around the threads before you make the connection and hand-tighten. Finish tightening with a wrench. Connect the line going to the faucet to the hot water outlet using the same materials.
4 WIRE THE UNIT. On a 240-volt circuit, the white wire will attach to one of the hot terminals, and the black to the other hot terminal— they're often labeled L1 and L2. The ground will go to the grounding screw on the unit. On a 120-volt unit, twist the white supply wire to the white wire in the unit, and twist the black wire to the black. Cover with wire caps, and tape the caps in place.