If only we would listen, water heaters would have a lot to tell us, their owners. Water heaters sorta like people, don’t appreciate not being heard. So, why do you think heaters fail on holidays and weekends? They just want attention! Most folks only pay attention when the heater has failed and they need a new one on Christmas morning, or some other inconvenient time. If you want to avoid that unhappy predicament, there are a few things you can do.
First, just have an admiring glance at the heater periodically. Has anything changed? Is there rust or moisture someplace? If it’s gas, is the vent pipe still hooked up? Is there a drain line from the temperature and pressure relief valve and is it piped to a safe location? Is it dry at the end of that pipe? Is anything stored on top or right next to your gas heater? I’ve seen the fire caused by a broom to close to the combustion chamber. It’s good to keep heaters from killing us with carbon monoxide, fire, or by blowing up. Some heaters CLEARLY don’t like not being paid attention to!
Next, it pays to understand why heaters die. The main neglect is the sacrificial anode has been used up and there is no longer any rust protection for the steel tank. It may be difficult to remove an old stubborn anode, but it’s far less work than replacing the heater. This is one clue you need to dig a bit to find. You might want to have a look at www.waterheaterrescue.com (WHR) for a lot more info on replacing anodes… and most anything else about water heaters! By the way, heaters just love having new anodes! The next heater killer is pressure. If water pressure is too high or if it fluctuates rapidly, this can cause the glass lining to crack and flake off, leaving bare steel to rust. Ideally, you want water pressure to be in the 40-60 psi range. Get an inexpensive 0-200 psi gauge and measure it. The heater’s drain valve is a good place to measure from. Also, watch the gauge when water is heating and no water is running. There is a gauge made that has a little red pointer, which shows you the highest pressure the gauge has seen. If it creeps up higher than the static pressure (static is when no water is being used) you know that thermal expansion, from heating the water is raising the water pressure in the entire house. This is common with homes that have pressure reducers or back-flow preventers. Sometimes there is a check valve in the water meter. A clue the heater may give you is the relief valve dripping periodically. Most open at 150 psi, so periodic dripping tells you the heater is suffering from too much pressure. Just because a relief valve doesn’t drip, doesn’t mean things are all good. In my area roughly one out of forty relief valves is plugged solid with hardness from the water. It’s like capping the line and gives you no protection at all. One in forty seems a bit too close to Russian roulette to me. You’ll see at WHR just how to test a relief valve so you know it’s working.
Sediment build-up in a tank also is not a good thing. In gas heaters, it slows heat transfer, causing overheating at the bottom and causing the glass lining to dissolve. Also, with gas heaters a rumbling noise can happen as water trapped in the sediment boils. In electric heaters, it can bury and burn out the lower element and be a cozy breeding ground for bacteria. Imagine just how bloated you would feel if you had all that sediment in you! WHR has flushing parts you can install (in your heater) to help reduce the problem.
Gas fired heaters can also give clues about how they are venting or not. On top of the heater is a “draft hood”. This exhausts combustion byproducts via a vent pipe to the outside. Sometimes if air pressures are wonky, you’ll see discoloration on the pipe nipples that live on both sides of the draft hood. If these nipples are rusty on one side or if insulation on them is melted, you know there is a venting issue. Additionally, if you see evidence of overheating towards the bottom of the heater, in front under the control valve, it’s more reason to check out the venting. Heaters like to breathe too! Having a carbon monoxide detector in the house just might not be a bad idea.
Another thing heaters sometimes do is provide less hot water. This could be a simple thermostat adjustment… thermostats do drift with time, but it could be a damaged dip tube. This is a plastic pipe inside of the tank, which delivers cold water to the bottom, so it doesn’t mix with the hot water. These dip tubes can get brittle with age and crack or just fall off. Or, the problem may have nothing at all to do with the heater. A cross connection in the plumbing can make it look like the heater is ill or in a bad mood. By mixing cold into the hot water, a cross connection can fool people into looking in the wrong place. If you shut off the water to your heater and open a hot tap, it should stop running in a few seconds. If it keeps running, there is a plumbing problem and the heater can remain happily blameless.
There is a lot more to discuss, but these are the main things that go wrong, along with their telltale clues… May your water heater get the attention it wants, so it can live a long and contented life, giving you hot water whenever you wish! It really would much rather live this way than having to think murderous or leaky thoughts! If you listen carefully to that heater you just maintained, you might even hear it say “Tanks!”.
Looking back over my working life of 50+ years, it seems clear that self sufficiency has always been the best way for me to be useful. Now, mix in a strong interest in water in its many forms and the wide world of animals and you'll know what's important to me.