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Water Heater Troubleshooting & Repairs

A water heater’s control valve should typically be set to 150 degrees F. or lower.

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Expert step-by-step instruction on how to repair hot water heater problems such not enough hot water in a gas or electric storage tank-style water heater.

Do you need to troubleshoot water heater problems or repair your water heater? Water heater problems normally become self-evident: A hot water faucet fails to summon hot water, you see dripping or puddling near the water heater, or the tank makes strange gurgling or popping sounds.

Though many gas utility companies will make a free house call to solve problems with a gas water heater’s burner or the gas supply to the tank, you’re on your own when it comes to other water heater problems. It helps to know how to solve basic outages yourself, as discussed below. For more difficult issues, contact a qualified local water heater repair person.

Typical water heater problems include a leaking tank (see Water Heater Is Leaking), not enough hot water, water that is too hot or not hot enough, strange noises in the tank, and discolored or smelly water. Most of these kinds of problems are relatively easy to diagnose and handle if you understand how water heaters work. See How a Storage Water Heater Works.

With a water heater, the most common complaint is that it doesn’t heat water properly. Either it doesn’t heat water at all, it doesn’t heat it enough, or it heats it too much. Because a gas water heater operates much differently than an electric water heater, most repairs regarding improper heating depend on whether the appliance is gas or electric. For handling problems specific to one of these two types, see Gas Hot Water Heater Repairs and Electric Hot Water Heater Repairs.

Before you proceed to the various water heater repairs in this article, here are a few helpful tips regarding safe, efficient water heater usage:

Foam pipe insulation can help quiet some noisy pipes. Photo: Frost King

Foam pipe insulation can prevents heat loss through hot-water pipes. Photo: Frost King

• Check the water heater’s temperature setting. Set the temperature control to about 150 degrees F. or lower if you have no dishwasher or if you have small children or elderly people in the home who might scald themselves.

• Insulate hot water pipes. To minimize the energy it takes to heat the water, insulate your water pipes if they run a long way from your heater to your faucets. If you can gain access to your hot-water pipes, from the basement, for example, put foam pipe insulation sleeves onto them to minimize heat loss.

• Periodically check the temperature-pressure relief valve, which keeps pressure in the boiler from building up too much. Lift or lower the lever on this valve. Water should drain from the overflow pipe. (For more about this, ee How to Replace a Water Heater’s TP Valve.)

Now, on to the repairs.

Problems such as leaks, noises, and odors are handled the same regardless of the heating method.
Two of the most common problems with hot water heaters are that they produce water that is either not hot enough or too hot. The quickest and most obvious first step is to adjust the temperature dial on the front of the water heater, wait a little while, then check the water temperature at a faucet. But if adjusting the temperature dial doesn’t do the trick, try the methods below.

Try adjusting the temperature dial first.

Try adjusting the temperature dial first.

Not Enough Hot Water

An undersized water heater is usually the culprit if it seems like you never have enough hot water in your home. If the problem is chronic—or if you’ve increased your needs for hot water by installing a big new soaking tub or high-flow shower head—you’ll probably need to get a new, larger water heater. Be sure to look into tankless water heaters because, with this type, you never run out of hot water.

On the other hand, if you’ve had enough hot water in the recent past but your water heater suddenly seems to supply less hot water, first check the dial on the water heater, as discussed above.

NOTE: If  outdoor temperatures have dropped significantly, your water heater must work harder to heat and maintain the cold inbound water, and the water cools more as it travels through pipes that run through unheated spaces. This calls for adjusting the water heater’s dial to a slightly hotter temperature.

Also make sure the water heater isn’t leaking. If neither of these issues are the problem, flush the water heater tank to be sure mineral deposits are not reducing the heater’s efficiency. To do this, please see How to Flush or Drain a Water Heater.

Attach a hose to the water heater’s drain valve and empty the tank.

This is also a good time to test that the temperature-pressure relief valve, which keeps pressure from building up too much in the boiler, is in proper working order. Lift or lower its handle. Water should drain from the overflow pipe. If it doesn’t work, see How to Replace a Water Heater TP Relief Valve.

If these measures don’t do the job, the dip tube that supplies cold water to the tank may be broken or cracked. This plastic tube is supposed to direct cold water to the bottom of the water heater tank, but, if it breaks or splits, cold water pours in at the top of the tank and mixes with the hot water that is on its way to the hot water pipes.

Either have the dip tube replaced by a water heater repair pro, or, if the water heater is out of warranty and showing other signs of age, consider replacing it.

Hot Water Is Too Hot

adjust water heater temperature©Don Vandervort, HomeTips

Mark the water heater dial and adjust it to a lower setting.

Clearly, the first thing to do if your hot water is too hot is turn down the temperature on the water heater’s thermostat dial. Note the present setting (or mark it with a felt-tip pen), and then turn it toward a cooler setting, wait a couple of hours, and see if the problem is solved.

If steam or excessively hot water shoots out of faucets, or you hear boiling sounds inside the water heater, the appliance may not be shutting off at its set temperature.

The job of the temperature-pressure (TP) relief valve is to release excessive pressure from steam buildup, but this valve may have been improperly installed, or it may be faulty. Either way, this condition can be dangerous, both because hot water and steam can scald people and because the water heater could rupture.

Turn down the water heater’s temperature and allow the water to cool, then replace the water heater’s pressure relief valve. See How to Replace a Water Heater TP Relief Valve.

Hot Water Is Discolored or Smells Bad

If your water has a strange odor, first determine whether the problem is with the source water or the water heater. If the problem is with both the hot and the cold water, or if only the cold water smells, the problem is more likely with your source water. Iron, copper, and other minerals can cause discoloration in water.  To solve these kinds of issues, consider installing a whole house water filter and/or a water softener.

If the problem is only with the hot water, in most cases the odor is caused by a reaction between the hot water heater’s anode rod and water that has a high concentration of sulfates. Let the hot water run for two or three minutes. If it smells a bit like rotten eggs, you can try flushing the hot water heater tank (see How to Flush a Water Heater). If this doesn’t solve the problem, the anode rod may need replacement by a water heater repair person.

If you smell a garlic-like scent, the pilot light may have gone out. Turn the gas valve control to OFF (you may have to push down to turn it). Wait until the gas smell has dissipated before relighting the pilot light. If the gas smell is strong and doesn’t dissipate, immediately turn off the gas supply valve, ventilate the space, and call a plumber or your gas utility company from a remote location.

Water Heater Makes Noises

Noises coming from a water heater can be caused by expanding and contracting metal parts; drips; or, more likely, minerals and hard water scale accumulations inside the tank or on an electric water heater’s heating elements. When heated, dissolved hard water minerals recrystallize and form scale that cakes onto interior surfaces, making the water heater less efficient and more likely to fail.

To minimize corrosive minerals through ionization, water heaters have a magnesium or aluminum anode rod, inserted through the top of the tank. To avoid scale in the first place, every few months flush out the tank. See Not Enough Hot Water for complete instructions on how to do this.

Here are some common water heater sounds you might hear:

Water heater pops, bangs, or gurgles

These sounds are caused by the buildup of hard water sediment heating up and exploding inside the tank. You can flush out the tank yourself, although by the time you’re hearing this sound the sediment chunks may be too large to pass through the drain valve. For more, please see How to Flush or Drain a Water Heater.

If you have an electric water heater, these sounds could indicate a buildup of scale on your heating elements; it may be time to replace these.

Water heater makes a boiling sound

If water sounds like it is boiling inside the tank, this could indicate overheating and a dangerous pressure buildup. Call a service professional immediately.

More Water Heater Repairs

For step-by-step instructions on specific types of hot water heater repairs, next see:

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