All About Water Heaters

What is a water heater?

When you look at one, you're not really seeing the water heater, only the sheetmetal shell. That's something worth remembering because the shell can look fine when the tank inside it is about to break.

Inside that is insulation. Inside the insulation is a steel tank with vitreous glass bonded to the inside to mostly prevent the tank from rusting. A gas burner at the base heats water and a flue takes the exhaust to a vent and out. Or electric elements heat the water. In both cases, the bottom of the tank is domed.

On the Day & Night at right, taken out of an apartment after 40 years of service, you can see the interior of the tank and the gas flue running up the middle. This is the same construction used today for gas heaters. An electric tank would be the same except that there would be no flue running down the middle, but rather, one or two electric elements jutting out from the side.

But in all instances, there will be one or two sacrificial anode rods screwed into the top and a plastic tube, called a dip tube, running down from the cold port. You can see the remains of the anode on the right, hanging like a stalactite.

Gallonage, Btu and what do I need, anyway?

This is a place where buying more than you need is going to cost you money, both up front in price and in the long run in higher energy bills, while buying less is mostly going to result in frustration. The first question is, what size heater do you already have and are you happy with it?

If not, there are factors you can use to compare one tank to another. Pay attention to gallonage, Btu input and first-hour recovery figures. Many people think, more gallons, more capacity, but Btu input is important, too. Some commercial water heaters have little capacity, loads of Btu. Ultimately though, figuring out need is as much art as science. Variables can range from whether you have low-flow showerheads to how long your teen-age daughter spends in the shower.

R-value (insulation)

If you go for the cheapest water heater you can get, odds are it will have an R-6 insulation rating. That's about minimum. If you paid a bit more, though, you could have up to R-20. That's an investment you'd get back many times over during the life of the heater.

Standby heat losses

All water heaters, including tankless ones, have some standby heat losses. Tank heaters lose heat through the walls of the tank and up the flue. Getting maximum insulation will cut those losses considerably.

Tankless gas ones often lose heat from the pilot light, while electrics lose it by being plugged in all the time.

Serious losses for all types of heaters, unless they are right next to the outlet being used, is, from the piping. That runs from the heater to the faucets. It's made of copper, mostly, sometimes steel. It radiates heat very well.

So if you want to cut standby losses, insulate the pipes, if you can, and when you install a tank heater, make heat traps out of copper flex lines. How? Use a longer flex than you need and make a big gooseneck in it, like a question mark. Heat will rise up the flex to the top of the gooseneck and no farther. The photo above left is of a commercial water heater, but the principle is the same. Heat will rise as far as the red lines, but not go into the blue because heat only rises. So insulating to a little beyond the top of the rise will be effective.

Anodes, glass lining and longevity

Why do water heaters break? Does anybody know? We'll let you into the secret. While a glass lining mostly protects the tank from rusting, due to limitations in the manufacturing process there is always some exposed steel. Also, some glass linings are more complete than others. So exposed steel is protected from rusting by the use of sacrificial anode rods. The principle by which they work was discovered 200 years ago by Sir Humphrey Davies, an Englishman.

When the tank is filled with water, a slow electrolytic reaction takes place whereby the anode corrodes and the steel is protected. When no anode remains, the steel rusts and the tank fails. If you soften your water, beware. That can increase the conductivity of the water and speed up the anode consumption.

How fast a given tank lasts is a function of use, water temperature, the quality of its glass lining and water quality -- and how many anodes it has.

Sutherlands sells water heaters in warranties of six, nine and 12 years. Longer-warranty water heaters generally have an additional anode rod in the hot port. It's also possible to buy a second anode made to screw into the port from www.waterheaterrescue.com and add it to a six-year-warranty tank. That will undoubtedly lengthen the life of the tank, but the warranty will still be six years. Whichever way you prefer to do it, having a tank with two anodes is another bargain like insulation, where spending a little extra money now will pay off in the long run. A 12-year-warranty water heater doesn't cost twice as much as a six-year-warranty one, and if a plumber is doing the installation, it's a small addition to the overall cost.

If your water heater is inside your home, a two-anode tank decreases the risk of a flood, as well as the likelihood of not having hot water at an awkward moment, like on Christmas morning. Even people whose tanks are in the garage or basement can have water damage to things left on the floor.

Another thing: some water heaters come with aluminum anodes. There are health issues connected with aluminum. Richmond heaters always come with magnesium anodes.

Sediment buildup and flushing

When hard water is heated, the minerals dissolved in it that make it "hard," settle out as sediment and fall into the bottom of a water heater. The sediment can build up enough to burn out lower elements on electrics and overheat the tank bottom on gas models.

The longer-warranty Richmond water heaters sold by Sutherlands come with a "self-cleaning" dip tube. The dip tube is a plastic tube that carries incoming cold water to the bottom of the tank to be heated and keeps it from mixing with already-heated water, which rises. The tube is engineered to keep the sediment from settling, thus forcing it to flow out of the tank as hot water is used.

However, copious usage is required for this to work well. If you use low-flow showerheads, or have unusually hard water, or you're buying a six-year-warranty tank, you might consider a flush kit from www.waterheaterrescue.com to expel sediment buildup.

Cutting the wait for hot water

If your water heater is at one end of your house and your shower at the other, frustration will be the result. That's because the water lying in the piping in between will cool off and it will take you what seems like forever to run the shower long enough to get new hot water through the pipes from the tank.

One solution to this is a recirculation system, either gravity-feed, or operated by a pump. Such a system keeps water circulating through the piping and returning to the tank so that when you turn the tap, there's no wait. Such a system cuts your water bill because you don't have to run so much down the drain to get the hot water flowing. But it will probably increase your energy bill, even if you insulate the pipes, because the heater will run more to keep the water hot. It can also be messy to retrofit a house with a recirculation system.

An alternative is a Metlund device. At the touch of a button a minute before you need hot water, it pumps cold water from the hot line back into the cold line and back to the water heater, thus drawing hot water from the heater without running the cold water down the drain. It's simpler to install than a recirculation system and heat loss is limited to the water that cools off in the pipes after each use. The Chilipepper appliance works in a similar way.

Explosion control

Nearly all water heaters are equipped with a safety device called a temperature/pressure relief valve. Its purpose is to open and vent water and pressure if temperature or pressure exceeds the valve's limit. Water heaters rarely explode, but when they do, it's much like a rocket launch. It's catastrophic, in fact.

T&Ps, as they're called in the trade, should be tested once a year by pulling up on the silver handle. Water should flow freely and stop when you let go of the handle. If it does nothing, or dribbles or drips, then it should be replaced. However, if one of those latter two possibilities occurs. banging down on the spindle of the handle will sometimes help the valve reseat and stop dripping/dribbling. People seldom test their T&Ps, but this is a $6 part that can save your house or maybe even your life. They are especially prone to gunk up with calcium in hard-water areas. Test your T&P!

Do-it-yourself, or maybe not

We at Sutherlands pioneered the concept of do-it-yourself in the United States, saving our customers truckloads of money in the process. Installing a water heater isn't that difficult, but there are enough dangers involved that we think that often people will do better to leave it to a professional, who not only knows all the codes, but knows the reasons they are codes. In particular, 220-volt appliances can be quite dangerous. We want our customers to be with us for a long time to come.

Smelly water

In some parts of the United States, there are anaerobic bacteria in the water -- often in wells -- that will react with normal anode rods to create hydrogen sulfide gas. You open the hot tap, you get rotten egg odors. Sometimes it also discolors laundry. The quick fix for a typical 40-gallon tank is to open it and pour a couple of pints of hydrogen peroxide into the water. Chlorine bleach will also work, but peroxide is a lot safer. Then open the taps to get the treated water into the piping and kill the bacteria there.

The long-term fix involves removing the anode(s) that came with the tank and replacing it with a special aluminum/zinc anode. Those are available at www.waterheaterrescue.com, which also contains considerable information about all aspects of water heaters and offers troubleshooting/problem-solving.

Clattering noises

If you can hear an annoying rattling sound, especially at night, suspect what are known as heat-trap nipples. These were designed to help water heaters meet federal energy conservation requirements. They consist of a nipple, which is a connector threaded at both ends, the plastic insert you can see at right, and a marble, which is inside.

The heat trap keeps heat from rising when the water heater is not in use. But it also is prone to rattle, especially if the water heater is equipped with a recirculation system that keeps water moving. And the piping will broadcast the noise all over the house. To solve the problem, simply take a pair of needle-nose pliers, firmly grasp the top part of the insert, work it loose, and throw away the marble.

Water heaters in apartments

If you are a landlord and are reading this, consider paying a visit to the commercial section of www.waterheaterrescue.com.
It will tell you how to get the most from new water heaters and save money and grief in the process. We'll be happy to source the water-heater end of the equation for you and Water Heater Rescue will provide the rest.

The Tank, a water heater forum

In September, Water Heater Rescue started a bulletin board and forum called The Tank, where people can go to get answers to problems and discuss issues. Its purpose is to promote exchange of knowledge and understanding among plumbers, builders, architects, apartment people and the public. So if you have a problem that you don't see here, considering looking at the site's troubleshooting sections or using The Tank.

Water heating from 100 years ago

They don't make 'em like they used to, which is too bad. There were many innovations from that period that are no longer in use today. Some designs were even superior, but because they cost more, they were relegated to the scrap heap of history. And undoubtedly, water heaters were vastly more ornate and beautiful, such as this Ewart Royal Geyser bath heater, than today's plain-looking steel cylinders. For a peek at water heating from a time when the idea of daily bathing was just becoming popular, visit the Weingarten Collection.

Randy Schuyler operates www.waterheaterrescue.com, which is dedicated to making sure water heaters function safely, efficiently and for as long as possible. He has known the Sutherland Family for many years.