How to test water heater element

Test elements

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2023

Buy multimeter Install battery. Setting 1: Rotate dial to 240-250Vac to test for electricity. Setting 2: Rotate dial to Ohms to test element as shown on this page. (upside down horseshoe symbol is ohms) 1) Use multimeter to test element 2) Do not drain water heater 3) Power is OFF during this test. Buy: Analog multimeter Multimeters Klein multimeter Electric testers Clampmeter for testing amp flow on line Resource: How to troubleshoot electric water heater
See cold resistance ohm chart	Test for ohm ... Ohms is resistance Volts squared divided by watts = ohms Watts and volts are printed on end of each element. 240 volt water heater, 4500 watt elements: 57600 divided by 4500 = 12.8 ohms However, there are a wide range of results and element can still be good. Applies to cold element, and not hot. Cold resistance: measuring ohms across both screw when no wires are attached to element and element is not heated. Hot water in tank raises resistance on element. Let element cool before doing ohm test so you are measuring cold resistance.

	Turn off circuit breaker Turn off 30 amp double breaker to 240Volt heater Turn off 20 Amp single breaker to 110 Volt heater
	Test for voltage using non-contact voltage tester. Advantage of non-contact voltage tester: ease and safety since wire nuts are not removed. Never assume power is OFF. Touch end of tester to each black, white, and red wire. Press button. If tester flashes repeatedly like alarm, then voltage is present. if tester flashes once, then that says no voltage is present. Buy: Non-contact voltage tester
Larger image	Test for voltage using voltage tester. Remove wire nuts. Applies to120V and 240V. Test Black to Ground, test Black to White, test White to Ground. If tester light comes on with any test, electricity is present. See basic water heater circuit
	Open panels on side of water heater Do not drain water heater to test elements. Remove insulation Older water heaters have fiberglass insulation covering element and thermostat. Newer water heaters have tight-fitting foam insulation. Newest tanks have thicker foam insulation. Foam insulation is not easy to work around. You may need to cut back the foam to work on parts. Remove as much foam as needed to access parts. Insulation must be put back when finished. When finished, thermostats and elements must be covered by insulation again or thermostats become exposed to cool air and will misread tank temperature. Always best to put safety cover back into place when finished.
	Remove plastic safety covers that sits over element. Pull off tab at top then pull off or unhook sides Replace covers when finished. Buy: Camco 08113 Upper thermostat shield 08103 Lower thermostat shield 08130 kit with both thermostats and shields
Larger image	Which element do you test? If water heater makes some hot water, then lower element is suspect. If upper element is burned out, water heater will have no hot water. Test both elements. If water heater is tripping circuit breaker, then test both elements and look for burned and melted wire. Resources: What to do if melted/burned wire is found Water heater is tripping breaker Troubleshoot electric water heater How water heater works How to wire thermostats Test electricity to water heater
	Tank must be full of water or elements burn out ...; called Dry Fire. If you replaced either element and water heater is still not working ... test upper element
	Take wires off element Use nose and eyes to inspect for burned/ melted parts and wires. If wires are burned/ melted then replace part and test wire for continuity. Resource: Test water heater wires Buy: Shop Amazon Tools - DEWALT Shop Amazon Tools - Black and Decker Shop Amazon Tools - Stanley
	Bolt-in and screw-type elements Water heater come standard with high density elements. Foldback elements, or low density elements spread the heat across more square inches of surface space, and perform better in circumstances of very hard water, and some other water conditions. If elements burn out frequently, use low density, or substitute lower wattage. Lower wattage means slower heating and slightly less first hour delivery. Buy: Water heater elements Low density element Resource Calculate first hour
Test element Set multimeter to read ohms	Good element passes 3 tests: Test 1: Element shows correct ohm reading Test 2: No reading on multimeter Test 3: No reading on multimeter Rotate dial to Ohms to test element Ohms is upside down horseshoe symbol Buy: Multimeters
Larger image	Watt and Volt rating printed on end of each element Important: Ohm test varies by watt and volt rating of each element. Resource: See ohm chart
	Test 1: Test across both screws Test across both element screws and resistance should read about 12.8 Ohms for 240-Volt 4500-Watt element. For 30 gallon tank with 3500-Watt elements, reading is about 16 Ohms. Open reading means element is bad. No reading means element is bad. Check watt and volt rating printed on each element Applies to COLD element. Water heater with warm water will change reading. Element wattage volts ohms 3500 watt 240 16 4500 watt 240 12-13 5500 watt 240 10-11 Ranges can vary widely, even with good multimeter. 'Volts squared' divided by watts = ohms Volts x volts is 'volts squared' 240 volts x 240 volts = 57,600 volts squared 57,600 volts squared divided by 4500 watt = 12.8 ohms Resource: See ohm chart

	Test 2: Test screws to metal shell Test each screw to bare metal part of water heater. Test both screws. If multimeter reads any Ohms at all, or if needle moves even tiny bit, then element is shorted and needs replacement see how
	Test 3: Test screw to element Test each screw to metal base of element. If multimeter reads any Ohms at all, or if needle moves even tiny bit, then element is shorted and needs replacement
- Results -
	If element passes all 3 tests Elements are good and passes all 3 tests Double-check results before putting wires back on elements. If elements burn out frequently, then install lower wattage element. Elements passes all 3 test but water heater still not working Push breaker fully off and then fully on Tank heats 21-40 gallons per hour Resource: Troubleshoot walk-thru
	Element has burned wire If element is not damaged, then Cut back wire and reconnect to element Resource: Replace element Test wire for continuity
	Element is bad Resource: How to replace element Full efficiency can be restored to electric heater Water heater must be full to loosen element, but must be empty before element is removed Buy: Water heater elements Low density element
	Element wrench Leave water heater full of water to loosen element Then drain water heater and remove element Buy: Water heater element socket 1-1/2" Camco heavy duty element socket Marathon elements are 1-7/8"

Buy from my links 5 year warranty Ultra Low Watt Density/ ripple Hard water element Resists high mineral count Minimum 15" diameter tank Buy: 240 volt: 4500 watt 4500 watt 13" diameter 5500 watt Camco ripple elements Reliance 5500 watt ripple	5 year warranty Ultra Low Watt Density/ foldback Hard water element Resists high mineral count Check minimum tank diameter Fits any tank above minimum dia Buy:240 volt: 2500 watt 3500 watt 4500 watt 5500 watt	Rheem/ no extended warranty Low Watt Density/ foldback Minimum 14" diameter tank Buy:< 240 volt/ copper non- resistorized: 4500 watt copper 240 volt Buy: 240 volt/ stainless steel non- resistorized: 4500 non-resistorized Amazon 5500 non-resistorized Amazon Rheem elements
$10 - $16 Camco/ no extended warranty Low Watt Density/ foldback Check minimum tank diameter Fits any tank above minimum dia Buy: 240 volt: 2500 watt 3500 watt 4500 watt 4500 watt 12 pack 5500 watt	$10 - $12 Camco/ no extended warranty/ High Watt Density Standard on all new water heater Can use foldback as replacement Match volts and watts Buy: 120 volt: 1000 watt 120 volt 8" tank diameter 1400 watt 120 volt 1650 watt 120 volt 7.5" minimum 1750 watt 120 volt 9" minimum 2000 watt 120 volt 9" minimum Buy: 120 volt copper: 2000 watt 120 volt Buy: 240 volt 1500 watt 2000 watt 12 pack 2500 watt 3000 watt 3500 watt 3800 watt 4000 watt 4500 watt	Use 1-1/2" socket to remove elements Buy: Camco element socket Tekton water heater socket Deep impact socket $20 16" breaker bar fits impact socket $7 Ordinary Residential element wrench Today's hex-head elements have rounded corners, and thinner profile. Making it difficult to hold wrench on element while turning. Socket is easier to use than ordinary element wrench. Use weight of water: Loosen element while tank is full of water. Then drain tank before unscrewing element.

Screw-in elements

Elements burn out frequently: install lower wattage element, or install low watt density element
Causes include:
a) Sediment in bottom of tank How to replace element and clean out sediment.
b) Very hard water. Install softener. Read about softener and anode depletion
c) Watt density of element too high. Change element. Install element with less than 3800 watt See image Read pdf
d) Aggressive high pH water. Test water.
e) Loose wire on element. Open covers and inspect all wires for loose connections and signs of burning.
Resource:
How to replace elements
Water heater formulas and terminology pdf

Buy:
Water heater elements
Low density element

Larger image
Volts and watts are printed on end of each element
Volts and watts are printed on end of each element
480 volt 4000 watt
or
415 volt 3000 watt
When voltage drops, the element wattage also drops

Typically 480 volt is common on 3-phase non-balanced commercial water heaters. The non-balanced 3-phase heater can be converted to single phase but attention must be paid to the element voltage and wattage

How to figure resistive wattage by volts
Ohm's laws says: Volts squared ÷ watts = ohms
Resources: See chart How to test element

Each element has volt and watt rating printed on end of element
If element is rated 4500 watts @ 240 volts.... then volts squared (57600) ÷ 4500 watts = 12.8 ohms
So 12.8 is the ohm rating for the element, no matter what voltage is applied

But what happens when voltage is reduced on the same element?? For example voltage is reduced to 208 volts instead of 240 volts.
Then 208 volts squared (43264) ÷ 12.8 ohms = 3380 watts... and the element does not burn as hot

What happens when voltage is reduced to 120 volts on same element?
Then 120 volts squared (14400) ÷ 12.8 ohm = 1125 watts and heating is reduced to 1/4 the original output

What happens when voltage is reduced on 480 volt, 4000 watt element?
480 Volts squared (230400) ÷ 4000 watts = 57.6 ohms/ and 57.6 is the ohm rating for element no matter what voltage.
So when voltage is reduced to 415 volts:
415 volts squared (172225) ÷ 57.6 ohm = 2990 watts (or 3000 watts as shown in photo)

What about increasing voltage instead of lowering voltage?
What happens when 480 volts is connected to element that is rated for 4500 watts and 240 volts? POW ! element burns out
480 volts squared (230400) ÷ 12.8 ohm element = 18,000 watts or 4 times the rating... and the element will burn out immediately

:What happens when 240 volts is connected to element that is rated for 2000 watts and 120 volt? POW again
120 Volt squared (14400) ÷ 2000 watts = 7.2 ohm
240 volts squared (43264) ÷ 7.2 ohm element = 6000 watts running through a 2000 watt element causing it to burn out

So buy element that is rated for the voltage Resource Elements and element replacement
Resource:
3-phase non-balanced / and conversion to single phase

	Element will not come out How to remove rusted element Drill, tap and use bolts and wrench to remove. Drain water heater before drilling into element Prevent rusted water heater. Anode rod is necessary so tank will not rust. Anode rod depletes and should be inspected 1-3 years with water softener, and 2-5 years otherwise. Loosen anode rod before draining tank so weight of water helps hold tank steady How to replace anode rod
	Water heater will not drain Do not drain water heater to test element. Water heater is drained only when replacing element Water heater will not drain Use household water pressure and washing-machine hose to flush open water heater for 5-10 seconds
Larger image	Re-install insulation over thermostat and element Caution: Insulation and cover must be re-installed or thermostat is exposed to cooler air and will misread tank temperature. How to replace water heater thermostat
Larger image	ECO reset button keeps tripping or circuit breaker keeps tripping: element shorted to ground across steel tank What happens: - Illustration shows why element-test requires testing between element screws and steel tank - 240Volt water heaters have 2 Hot wires. Each hot wire is called a leg. Each leg is 120Volts with 240Volt potential when both legs are connected together. Difference between 120Volts and 240V - Thermostats turn off one leg in the 240Volt circuit. - When thermostat turns ON, that event connects the second leg to the first leg, and element turns ON. - In some cases, the element can crack or short. In most cases, the short will trip circuit breaker. - If the crack or short is far enough along in the element, the resistance will not cause breaker to trip. The short travels across steel tank hull to the ground wire at top of tank. - The ground wire will complete 120Volt circuit. Elements will heat up using 240Volts or 120Volts. Element continues heating, and will not turn off. This causes runaway heating, and TP valve will release water or ECO reset will trip. How to convert water heater to 120volts
	Breaker keeps tripping Read more: Circuit breaker keeps tripping New water heater not working

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Use 1-1/2" socket to remove elements