Electric water heater element test procedure:

this article describes how to test electric hot water heater heating elements, what readings to expect if using an ohmmeter. This article describes the steps in testing electric hot water heater heating elements, followed by a guide to replacing a bad heating element.

This series of articles describes how to inspect, operate, diagnose, and repair electric hot water heaters. The articles at this website will answer most questions about electrical water heaters as well as many other building plumbing system inspection or defect topics. Reproduction of this web page electronically at other websites is prohibited.

How to Test Electric Water Heater Heating Elements

Operating Sequence of Electric Water Heater Elements upper and lower heating elements

Note: Once you have diagnosed which heating element is bad, also seeELECTRIC WATER HEATER ELEMENT REPLACEMENT

Because the electric water heater might be failing to work due to loss of electrical power to the unit, or because of a malfunctioning high-temperature cutoff switch, you should also see the test steps

at ELECTRIC WATER HEATER HIGH TEMP CUTOFF TEST

Electric water heater drawing (left) showing the sequencing procedure for electric water heater elements is provided courtesy Carson Dunlop Associates, used with permission

Electric water heaters have two heating elements - thick metal loops that get hot when electricity flows through them, similar to the burner on an electric range.

The lower heating element heats cold water as it enters the hot water tank. (Incoming cold water is delivered to the bottom of the tank through the dip tube.)

This element works the hardest, is on the most, and so often is the first to burn out. The upper heating element acts as a "booster" to heat water when there is a high demand. This element heats only the water in the upper portion of the hot water tank.

As we introduced earlier, if there is some hot water but it is limited in quantity or temperature, just one of the heating elements may have failed.

Scale coating a water heater element can also reduce the quantity of hot water (or cause heating element failure) - a topic we review in more detail

at WATER HEATER SCALE DE-LIMING PROCEDURE
and
at WATER HEATER NOISE DIAGNOSIS, CURE

If the electric water heater produces the same old quantity of hot water, but water is only tepid rather than hot, we suspect that the top water heater element has burned out. The bottom element is heating the entire tank but it is not capable of heating the water to the same high temperature as if both elements were working. Long tepid shower - bad top water heater element.

If the electric water heater produces the same old hot water temperature, but the quantity seems drastically reduced, we suspect that the bottom water heater element has burned out. Only the water in the top of the tank is being heated. Cold water enters and remains at the bottom of the water heater. So our hot water is plenty hot but we run out in just a few minutes. Short hot shower - bad bottom water heater element.

As we're about to show in detail, one can test a water heater heating element by a simple procedure using a continuity tester or a volt-ohm meter- a VOM.

See DMM DIGITAL MULTIMETER HOW TO USE

For details on how to use electrical test equipment see DMMs VOMs SAFE USE OF

and see VOLTS / AMPS MEASUREMENT EQUIP

Steps in Testing an Electric Water Heater Heating Element - Good Method

Reader Question: our water won't get hot - electric water heater

Water will not get hot when turn on hot water in house - Claude 11/29/12

Reply:

Claude, you may need to replace your water heater elements. See the test steps given in the article below:

1. Turn off electrical power to the water heater - you should have done this earlier if you read the instructions above. Turn off power at the water heater circuit at the main electrical panel.
2. The water in the heater should be lukewarm or colder. If the water heater is hot, run hot water in the building (with the water heater electrical power OFF) until water flows lukewarm or colder.
3. Disconnect the electrical wires at the heating element terminals. (This is so whether testing upper or lower heating element).
4. Test for current flow: Use a VOM, DMM, or Ohmmeter or multimeter set to read "resistance" or "ohms" as follows: connect one alligator clip or touch one probe of the VOM to each terminal on the water heater element.
   
   One probe touches one terminal, the other probe touches the other terminal. If the Ohmmeter needle doesn't move (or no reading is given on the DMM) then the electric water heater heating element is defective and needs to be replaced.
   
   If the ohmmeter needle moves or you get some Ohm reading (other than infinity) then the heating element is OK and you are ready to test the other heating element on the heater. In sum, if there is "continuity" through the heating element it is working. If there is no continuity (no electrical current can flow) then the element has failed.

Testing an Electric Water Heating Element for a Short Circuit - Crude Method & OHM Table for Water Heater Elements

We do not usually make this test but we include it here as it appears in some diagnostic procedures for electric water heaters. The water heater element OHMS chart (left, courtesy A.O. Smith) describes the actual ohm reading you'd expect if testing a factory OEM heater element of the wattage shown.

Even without that level of detail there is a simple test you can perform to see if an electric water heater heating element is in good working order:

1. Turn off electrical power to the water heater - you should have done this earlier if you read the instructions above. Turn off power at the water heater circuit at the main electrical panel.
2. Remove the access panel cover and insulation from the top or bottom water heater element (described above)
3. Connect the alligator clip or test terminal of your continuity tester to one terminal of the heating element. That's the wire and screw right on the heating element itself.
4. Connect the other probe of the continuity tester (or VOM) to a bolt or bracket that holds the heating element in position.
5. If the test light goes on, the buzzer sounds, or your VOM (set to Ohms) indicates continuity, there is a short circuit in the heating element and it needs to be replaced.

More water heater element test recommendations are in the Residential Gas and Electric Water Heater Handbook [PDF] provided by A.O. Smith and linked-to atReferences or Citations

Causes of Heating Element Failure on Electric Water Heaters

Besides old age and high usage, if your building water supply provides hard water (high in mineral content), scale build-up on water heater elements can lead to their demise.

See WATER HEATER NOISE DIAGNOSIS, CURE for details about removing scale from a water heater.

 

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Reader Q&A - also see RECOMMENDED ARTICLES & FAQs

On 2020-10-23 - by (mod) -

John

Are you testing the water heater element with

- all power to the heater OFF (so you don't get killed
and

- wires disconnected from the heating element?

If not let's try that.

If you still get infinite resistance or zero resistance then the heater element is probably shot.

On 2020-10-23 by John M Adams

My multiple will not work on ohms x 1k it only works on the highest scale and I'm reading continuity through the element . Could this be reading ingredients through the water because of the high scale and by element be bad ?

On 2019-12-16 by Anonymous

reading of 118 of power going in and out of elements

On 2018-10-18 - by (mod) -

Zam

If the ohmmeter needle moves or you get some Ohm reading (any resistance other than infinity) then the heating element is OK .... In sum, if there is "continuity" through the heating element it is working. If there is no continuity (no electrical current can flow) then the element has failed.

Thanks for asking

Watch out: If your electric kettle is causing a circuit breaker to trip or a fuse to blow it has an internal short circuit and is unsafe to use. Replace it.

On 2018-10-16 by Zamani

What could be a possible fault that cause an electric cattle to trip the earth leakage?

What is an acceptable resistance reading, when testing terminal of an element and its body?

On 2018-03-21 - by (mod) -

Mox

As far as I know the *insulation* resistance is not tested on a water heater element, nor on its wiring, in any normal building test process.

Perhaps we can start by clarifying the question. Good luck on your test.

On 2018-03-21 by Mox

Two precautions to be considered when testing insulation resistance test on water heater circuit

On 2017-12-17 - by (mod) -

Anonymous,

The major problem of water overheating is scalding burns to building occupants, in extreme cases causing death.

"Best quality thermo stant" is not a phrase I understand.

It sounds as if you're asking quiz questions. Good luck on the test.

On 2017-12-17 by Anonymous

What is the major problem of water heater is over heating

...

Continue reading  at ELECTRIC WATER HEATER ELEMENT REPLACEMENT or select a topic from the closely-related articles below, or see the complete ARTICLE INDEX.

Or see ELECTRIC WATER HEATER ELEMENT TEST FAQs - questions & answers posted originally on this page

Or see these

Recommended Articles

• DMM DIGITAL MULTIMETER HOW TO USE
• ELECTRIC WATER HEATER ELEMENT REPLACEMENT
• ELECTRIC WATER HEATER ELEMENT TESTS
• ELECTRIC WATER HEATER REPAIR GUIDE - home
• WATER HEATER NOISE DIAGNOSIS, CURE - remove scale from noisy water heater.

Suggested citation for this web page

ELECTRIC WATER HEATER ELEMENT TESTS at InspectApedia.com - online encyclopedia of building & environmental inspection, testing, diagnosis, repair, & problem prevention advice.

Or see this

INDEX to RELATED ARTICLES: ARTICLE INDEX to WATER HEATERS

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Citations & References

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