Test elements
Test elements |
How
to test water heater element |
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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: Multimeters Resource: How to troubleshoot electric water heater |
 See cold resistance ohm chart |
Ohms is resistance Volts squared divided by watts = ohms 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 ... ohms is a measure of resistance. Let the element cool before doing ohm test across both screws so you are measuring cold resistance. Hot wires have more resistance than cold wires... including resistance elements ... and the ohm meter measures resistance. Watts and volts are printed on end of each element. |
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Turn
off circuit breaker Turn off 30 amp double breaker to 240Volt heater Turn off 20 Amp single breaker to 110 Volt heater |
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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 |
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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 |
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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. |
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Remove plastic safety covers that
sits over element. Pull off tab at top then pull off or unhook sides Replace covers when finished. Buy: Upper element terminal protector Lower element terminal protector |
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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 |
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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 |
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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 |
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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 |
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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 |
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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 |
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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 |
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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 |
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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 - | |
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If element passes all 3 tests Elements
are good and passes all 3 testsDouble-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
workingPush breaker fully off and then fully on Tank heats 21-40 gallons per hour Resource: Troubleshoot walk-thru |
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Element
has burned wire Resource: Replace element Test wire for continuity |
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Element
is bad 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 |
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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 $25 - $47  5 year warranty Ultra Low Watt Density/ ripple Hard water element Resists high mineral count Minimum 15" diameter tank Buy: 240 volt from my associate links: 4500 watt 4500 watt 13" diameter 5500 watt Camco elements |
$13 - $26 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: 120 volt 1500 watt 120 volt 8" minimum 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 6000 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: 240 volt 1500 watt 2000 watt 12 pack 2500 watt 3000 watt 3500 watt 3800 watt 4000 watt 4500 watt 4500 watt 12 pack Buy: 120 volt copper: 2000 watt 120 volt Buy: 240 volt copper: 1500 watt 240 volt 2000 watt 240 volt 3000 watt 240 volt 3000 watt 240 volt 5500 watt 240 volt |
 Use 1-1/2" socket to remove elementsBuy: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 |
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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 |
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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 |
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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 |
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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 |
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Breaker keeps
tripping Read more: Circuit breaker keeps tripping New water heater not working |
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