Retrofitting Your Water Heater

One of our goals is to convince you to keep your current water heater running by retrofitting. This can save you a lot of money, not only for a new tank, but in plumber's installation costs, while ensuring that you have peace of mind about the condition of your heater.

People fear the rumbling noises that sediment makes and they fear an unexpected flood in their home or garage. Retrofitting means checking and changing anodes and controlling sediment buildup, as well as use of fittings that make maintenance possible without bringing in a plumber.

This section is devoted to explaining what parts are needed and the best way to utilize them. For guidance on checking your tank's condition and the hands-on details of retrofitting, go to Know-how.

The tank at right, which provides most of the rest of the examples on this page, is a retrofitting success story. It's our own water heater, a Kenmore, and has lasted about three times longer than what is typical where we live (26 years old in 2007) because we've retrofitted it and maintained it.

A key aspect of retrofitting involves replacing a tank's original anode when consumed or possibly adding a second anode to the heater. If you're in a hard-water area, it also involves adding a flush kit and setting up a schedule for flushing.

However, think twice about adding a second aluminum/zinc anode if you're having odor problems. It may make them worse.

Another aspect of maintenance is checking a heater's temperature/pressure relief valve (T&P) annually. People don't like to do that because residential ones are prone to failure, and thus, replacement. But it's a $6 part that can keep your house from being blown up.

How it's installed -- and other aspects of tank setup -- have a lot to do with how hard it is to replace.

As always, we'd like to point out that some skill is required for all this. If you have the slightest doubt as to your skills, get professional help.

Shutoff and connections

First, if the valve and connections you already have work just fine, don't necessarily replace them just because of what we say here. At the same time, we think these are important things to mention, if not for now, for the future.

Most of the time, the cold-water shutoff is going to be a gate valve. They usually work when they're installed, and often fail when they're needed, some years later. And not infrequently, we see soldered hard copper plumbing connecting the tank and plumbing. We prefer copper flex lines with threaded connectors. They make access to the tank much easier.

A few years ago (May 2004), we went to check our anode and T&P. When we tried to close our old gate valve, it worked. The anode was still in good condition, so we put it back. But the T&P was bad; it dripped. When we went to replace it a few days later, the gate valve wouldn't close completely. We had to shut the water off at the main.

Replacement of the bad gate valve by a brass ball valve was made easier because the gate valve was threaded on both ends. It could be replaced simply by unscrewing instead of unsoldering.

It's common to find ball valves and even flex lines soldered on. We prefer threaded fittings wherever possible because it means there's a good chance you won't need a plumber if something needs to be replaced.

That's the case with the ball valve (red circles at right show the threaded fittings). Easy off, easy on. Here, a brass nipple connects the ball valve to a new threaded flex connector.

Notice also that we used pipe-thread seal tape on all the threads (the white stuff). That makes it much easier to disconnect fittings if that becomes necessary.

Sacrificial anode rods

The most important part of retrofitting involves checking, and occasionally replacing a water heater's sacrificial anode rod. Likely you've never heard of that, but it's been used in water heaters for more than 50 years and has many other applications. Follow the link to learn more. And then come back!

Threaded connections are better than sweated ones for maintenance purposes

In brief, though, anodes corrode slowly and by doing so, protect a small amount of exposed steel inside a water heater. There's a reason that water heaters are warrantied to six years. That's how long the makers think the anodes will last. But their consumption depends a lot on water quality, and that varies widely across the country.

The photo at right is not from our tank, but we include it because it shows a hex-head anode in its own port, about where you'd expect to find one on many tanks, and two pipe nipples.

On some tanks, you'd find an anode under the one with the pink top. If you can't find a hex nut, there's a good chance the anode is in the hot port, a part of the nipple.

Exposed hex anode on top of water heater

Lightly corroded anode rod pulled half out of our tank

The photo at left shows our anode sticking out of the tank. It was functioning normally, with good corrosion from one end to the other. Bare wire was starting to show at the top inch below the hex head and for an inch at the very bottom, but it was mostly intact. The rule of thumb is that when there is six inches of bare wire anywhere along the rod, it's time for a new one.

We had had an aluminum/zinc anode in the tank for quite awhile for smelly water problems, but we decided to change back to a magnesium one. The water seems to have changed because we've had no new odor problems. Magnesium protects better.

If you soften your water, you need to check more frequently because salt can vastly speed up the reaction whereby the anode is consumed.

Also, always be sure and use pipe-thread seal tape when putting an anode back in a tank. It makes it MUCH easier to remove the next time.

If you have limited overhead clearance, you might need a flexible anode. It is one that has been milled down to the core wire on a lathe. The resulting segments can be bent and straightened about three times. After that, they snap, but it does provide a way to get an anode into a tank without removing the tank.

We generally recommend putting two anodes in a tank, if possible: one hex-head anode like the one from our tank, and a combo or outlet rod that combines an anode, hot-water outlet and plastic-lined steel nipple and screws into the hot port.

We strongly favor magnesium anodes over aluminum ones unless there are smelly-water problems. We have health concerns about aluminum. Also, being a less reactive metal, it doesn't protect the tank as well as magnesium. Finally, it generates an enormous amount of corrosion byproduct, which vastly adds to the sediment buildup on the bottom of the tank.

Butif you have odor problems, aluminum/zinc anodes can solve them, where magnesium or pure aluminum anodes will stink to high heaven. There are the same issues as with aluminum, but the alloy rods provide the cheapest fix we know to this problem. Another, though, that will avoid the aluminum issues, is a powered anode, which lasts indefinitely, although it also costs quite a bit more.

We're going to be out of town on family business from April 11 to April 22 and unable to fill orders, although we'll still be in e-mail contact. Any order made after noon PDT on April 10 won't be filled until our return. Just thought you should know.

Sediment control

When you heat hard water, minerals settle out of it into the bottom of water heaters as sediment. There, it does all sorts of unfortunate things. For the full story, visit the sediment page. And then come back!

Suffice to say that if you're in a hard-water area, you're going to have sediment and even if you follow the manufacturer's instructions and regularly drain your tank, you're still going to have sediment.

Why? Well, if you could look inside any water heater, you'd see the bottom is domed. And with gas heaters, there's a big flue dead center. Those are obstacles to efficient flushing. When you drain your tank, all you get is the sediment lying between the bottom of the dip tube (that's the cold-water inlet tube, and more on that in a moment) and the drain valve. Everything else stays put, causing noise, burning out elements in electric heaters, and slowing heat transfer in gas heaters and overheating the bottom.

Price: $42

Some newer tanks claim to be self-flushing. The idea is to keep the water so stirred up that sediment never gets a chance to settle down. Let's just say we have our doubts that this will work in most situations.

Then there are folks selling magnets that go on the piping, supposedly polarizing the water and doing amazing things. Trouble is, while there are numerous testimonials, there never seems to be any science. More doubts.

You'll probably say, "You just want to sell us a curved dip tube." You're right! Because we know it works. The only thing we know that works, except for vacuuming. That works, too, but it's not something you can usually do yourself.

Standard dip tubes are straight. They bring cold water to the bottom of the tank to be heated. We've taken straight ones and bent them -- mostly over the stove, and it's tricky. Too little heat and it kinks. Too much and it melts. Anyway, with a curved dip tube in your tank, aimed in the right direction, and a straight-path, brass, ball-valve drain assembly to replace the junk that comes with many heaters, you can make the water swirl around the flue and domes and blow the sediment out of the tank.

Now, a word about dip tubes in general. With age, they get brittle and break or split. Say 10 years or more, but there's no firm rule. If your water heater suddenly doesn't give as much hot water, think first about the dip tube. If it doesn't do its job, cold water coming in will mix with already-heated water going out.

The one at right came out of our tank. For reasons we'll explain in a minute, we decided it was worth a look-see. This used to be a curved dip tube. No longer. Retrofitting is about keeping an eye on things.

We wanted to check ours because some years back, there was a fair-sized scandal. A company that makes almost all of the dip tubes used in the U.S. changed its formula for plastic, with the result that in some conditions, the plastic disintegrated. The key period was August 1993 to March 1996. This tube was made in February 1994. Surprise!

One of the dead giveaways is if you start finding little bits of something clogging your aerators. Or you have less hot water, of course.

If you have a tank made in the critical period and you'd like to sue, sorry; somebody already beat you to it. The class-action settlement's terms expired several years ago. On the other hand, if you keep an eye on the anodes, change the dip tube, and make sure the T&P works, your water heater could yet shed big, hot, sediment-free tears at your funeral. It's a lot simpler-made than you are.

Temperature/pressure relief valve (T&P)

As we said earlier, how this part is installed has a lot to do with whether you need a plumber or just a pipe wrench.

The T&P unscrews from the tank and is no big deal to remove, especially if it's been installed with pipe-thread seal tape. What's connected to it and how is the sticking point. Code requires, at minimum, a pipe leading to within about six inches of the floor so that, if the valve opens, someone standing nearby won't be sprayed with hot or scalding water.

Our tank has a single threaded pipe serving that function. However, it's not uncommon for these drain lines to be plumbed with soldered copper piping to a drain or through a wall and outside. If right-angle turns are involved, it's going to take soldering expertise to replace the valve, since the drain line will have to be cut and resoldered to be able to unscrew it.

The photo at right provides one way of solving that problem. A brass union connects a copper pipe screwed into the T&P with the rest of the drain line. First the union can unscrew, allowing the upper part to be unscrewed from the T&P and then the T&P from the tank.

The shutoff valve photo toward the top of the page provides the clue to another way: use a brass nipple and copper flex line to connect T&P and drain line.

Something important: T&P drain lines should always go generally down and out. And the temperature probe at the bottom of the tank must extend into the tank. For some examples of how NOT to do these things, check out the Closet of Horrors.

Union on temperature/pressure relief valve drain line

Limed up temperature/pressure relief valve from our tank

As to testing, you do that by pulling up on the handle, holding it a few seconds and letting go. Water should flow through the line while the handle is raised and stop when you let go. If it won't let water through, won't stop running, or won't stop dripping within a few minutes, it should be replaced.

The T&P at left is ours. Note all the sediment coating the temperature probe and caking the interior. No wonder it wouldn't stop dripping! This is often why these valves fail -- they "lime up."

That nearly concludes this section. Remember to check your water heater once in awhile. Leaks outside the tank can destroy it as surely as leaks inside.

Many of the parts we've talked about are very hard to come by, so we offer some of them. T&Ps you can find in any hardware store. But anodes are fairly esoteric. And curved dip tubes simply don't exist unless we make them. Check those out in Products.