Expert step-by-step instruction for water heater troubleshooting and repairing hot water heater problems such as no hot water.
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Do you need to troubleshoot water heater problems or repair your water heater? Water heater problems normally become self-evident. For example, a hot water faucet fails to summon hot water, you see dripping or puddling near the water heater, or the tank makes strange sounds. Here you’ll find expert advice for water heater troubleshooting and DIY repair.
Though some gas utility companies will solve problems with a gas water heater’s gas supply, they won’t fix other water heater problems. Either you fix it your self or you call a pro to repair it. Calling a pro often means waiting a day or two without hot water and then paying a healthy repair bill. Consequently, 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. You can diagnose and handle most of these problems if you understand how a storage water heater works.
With a water heater, the most common complaint is that it doesn’t heat water at all. Because a gas water and electric water heaters are quite different, fixing a water heater that doesn’t work depends on the type. (A gas water heater has a burner at the bottom and a flue at the top; an electric one is powered by a large electrical hookup.) Please jump to one of these two pages for the appropriate water heater troubleshooting and repair advice:
Two of the most common problems with hot water heaters are that they produce water that is either not hot enough or too hot. Before you do anything else, 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 water heater troubleshooting methods below.
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. Then continue with the following water heater troubleshooting advice.
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 your water heater doesn’t leak—check around its base for signs of water. If neither of these issues are the problem, flush the water heater tank to clear out mineral deposits. These reduce the heater’s efficiency.
Also test that the temperature-pressure relief valve, which keeps pressure from building up too much in the boiler. 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—a new water heater is likely to operate more efficiently.
Hot Water Is Too Hot
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 it isn’t continue with the following water heater troubleshooting advice:
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.
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.
Dealing with Hot Water Odors
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. A flexible anode rod is easier than a long, rigid one to insert into a water heater if there is limited space above the tank. If you need help, call 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.
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 & Tips
For step-by-step instructions on specific types of hot water heater repairs, next see:
- Gas Hot Water Heater Repairs
- Electric Water Heater Repairs
- Water Heater Is Leaking
- Tankless Water Heater Repairs
Here are a few helpful tips regarding safe, efficient water heater usage:
• 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 water 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, see How to Replace a Water Heater’s TP Valve.)
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