If your electric water heater is not heating or is running out of hot water fast, you might have a problem with the heating element(s).
But don't worry. This article will help you diagnose the problem by explaining how to test an electric water heater element with and without a multimeter.
Also note that depending on your heating device, you might have one or two heating elements, with one or two thermostats, requiring you to check one or both elements.
Here, we will show you how to test an electric water heater element and diagnose a bad element. This test can also detect issues such as: why there is no hot water, or hot water is not hot enough.
When testing the heating elements, we mainly perform the continuity test, which shows us whether there is an obstruction in the electrical element or not. That means if there is continuity, the part is good, and the electricity can flow through the element without disruptions.
If there is no continuity, the element has failed the test because it is broken and should be replaced. And if you are still trying to figure out where the problem is, this article can tell you if your heating element is bad.
The best way to test a heating element is to use a device called a multimeter, whether manual (analog) or digital.
By using this instrument, and in addition to continuity check, the element test will show you how much resistance is there in a closed electrical current.
You can also test water heater elements without a multimeter, using a continuity tester or ohmmeter.
Before performing the test, ensure the multimeter's dial is in the lowest OHM resistance settings.
Also, you might have to calibrate the meter so it can read precisely.
Most multimeters come with two plastic probes (red and black) and metal leads at each end used to make contact. Use the plastic tubular sections for handling.
Touch the metal leads together with the dial in the OHM resistance mode. While the connection is made, check the multimeter and see if the needle of your manual (analog) manometer is in the zero position. If it is not, make the adjustments.
Setting a digital multimeter for testing is similar to the manual type, but instead of checking the needle position, you have a large digital screen, or you might have the option to set the dial to tone mode.
If the heating elements are in good working condition, your multimeter should show between 10 and 30 ohms (depending on the voltage). This indicates continuity.
If there is no reading or the reading value is very low, your heating element has no continuity, which is not good.
One of the reasons why there is no continuity is that the element has shorted out.
And here is the test to confirm that:
Did you know that you can test a water heater element without a multimeter?
You can simply use an ohmmeter or a continuity tester for the continuity test.
The procedure is the same. Note that the multimeter is a more advanced and multi-purpose instrument that can also be used as an ohmmeter, continuity tester, voltmeter, and ammeter.
So, when both tester leads or alligator clamps are placed on each element's screws, the continuity tester will illuminate or make a beeping sound if the element is in good working condition.
An ohmmeter helps you perform a resistance test which is more accurate than the above continuity test. It provides you with specific values, which you then compare against the element's specs. If you need information about the resistance values, keep reading to find out how to calculate them.
You can use both instruments to test if there is a short circuit within the heating elements.
You need to connect the continuity tester leads or alligator clips to one element screw and the other to the element flange. If the tester illuminates or makes a beep, there is a short circuit inside your water heater element, and it must be replaced.
While we mentioned the recommended range of resistance before, you can calculate it as long as you have the correct info.
In order to calculate the resistance of the heating element, we should use the formula: R=V*V/P; where R is the resistance, V is the voltage, and P is the power of the heating element.
If the heating element has a power of 3,500 W and the voltage is 220V, using the above formula will get us the following:
R= (220*220)/3,500=14 Ohms.
So, an element with 3500 watts will give us 14 Ohms, while an element with 5500 watts will show 9 Ohms (for the voltage of 220 volts).
As we mentioned, an electric water heater should have between 10 and 16 Ohms of resistance (plus/minus a few Ohms). Resistance depends on the unit's size, power of the heating elements, and voltage (110 volts is standard in North America and 220 volts in Europe).
Testing an electric water heating element for a potential problems is easy and doesn't require special skills and tools (except a multimeter or other testers).
So, what's next, you will ask?
Well, that depends on whether your testing showed a problem or the resistance is within the water heater specifications.
If your water heater element is broken (malfunctions), use this article to see how to replace it.
If your heating element is good, you need to dig deeper and find the cause of the problem. You can use this comprehensive guide to get more information on troubleshooting and repairing electric water heaters.