| How to test element How to troubleshoot electric water heater Look at water heater efficiency numbers  |
 Whirlpool site Whirlpool Energy smart electric |
Elements
screw into side of tank and come in many shapes and wattages  Check side of tank for wattage <> tank wattage is element wattage |
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Upper and
lower thermostats clip into mountings and read temperature through
tank wall. Reduce temperature and save
3-5%
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| In the past, EnergyGuide numbers on water heaters were large and easy to compare ... |  |
| ... but now, print is small, and yearly cost estimates are much lower than past years. If there were breakthroughs in heating efficiency, why disguise with tiny print? |  |
Find age of water heater
How electric water heater works:
Electric water heaters do not require air supply. Unlike gas water heaters, electric heater can be installed inside any unventilated space, like a closet with door closed, since electric water heaters are not burning fuel and require no incoming oxygen supply. Do not expose water heater to rain or water. Wet water heater is dangerous. Do not touch leaking water heater or water heater that is wet or was flooded without turning OFF power.There is no air inside tank. When hot water faucet is turned on, hot water immediately leaves top of tank. Hot water travels through pipe until it reaches faucet. At same time, new cold water enters bottom of tank through dip tube pipe. Read about dip tube
Immediate exit of hot water, and entry of cold water causes tank to activate element. To save energy, do not turn hot side faucet on when using only cold water.
Heating is done by electric elements. Tanks have 1 or 2 elements depending on design. Elements are similar to electric stove burners except they have elongated shapes and are designed to be immersed in water. Elements instantly burn out if no water is inside tank. Elements burn out for different reasons and can be replaced. In 2-element tank, if lower element burns out, the amount of hot water is reduced. If upper element burns out, the lower element stops receiving electric signals so neither element works and no hot water is available. See how to troubleshoot electric water heater.
Image shows tank with 2 heating elements called upper and lower elements. Elements are controlled by upper and lower thermostats. Thermostats read temperature through side of tank and turn elements ON and OFF. Residential water heater thermostats can be manually set to temperatures between 90º to 150º. Higher settings use more electricity. Save money by turning down thermostats For each 10º reduction, save 3-5% operating cost. See how to turn down thermostat.
Both elements are never ON at same time unless specific wiring is changed. See how thermostats work. Upper thermostat is main controller. It turns on upper element until top 2/3 of tank reaches temperature setting. After that, upper thermostat turns-off upper element and sends power to lower thermostat which turns on lower element. Lower element runs until tank reaches temperature setting.
During 'standby' between hot water use, lower element maintains tank temperature. Lower element keeps water hot by turning-on 3-4 minutes each hour throughout day and night which equals 126Kwh - 216Kwh each month for standby operation depending on tank rating and seasonal temperature. See math charts. Once hot water is used again, cold water quickly fills tank and elements are activated and heat cycle repeats.
Lower element is key factor in 'standby loss.' Water heater manufactures have targeted both elements for wasting electricity. They added electronics to upper thermostat that control initial heating, set lower thermostat 10º less than upper thermostat, and added better insulation to top pipes.
Why is the yearly cost-estimate so low on water heaters compared with past years?
See cost of running electric water heater at various rates.
Manufactures have added 2" foam insulation to most products. Some tanks are 'self-cleaning' to avoid loss of efficiency. See about cleaning tank to maintain efficiency. Manufacturers have turned down thermostats from 135º to 120º, or lower. They have re-estimated the amount of hot water consumed by families. These changes plus reducing consumption always save money. And over entire year, differences add up to dollars per month. But it still takes same number of Kilowatthours (Kwh) to heat a pound of water. The physics hasn't changed. And every pound of hot water that leaves the tank is replaced by cold water that is heated and kept heated until next time hot is used. See Water heating math
How to wire off-peak water heater.
If great strides were made in electrical efficiency, it would spark a scientific revolution and somebody would be shouting. Read about electric water heater efficiency. Instead EnergyGuide numbers that estimate yearly cost have become small and hard to see. The numbers seem amazingly low compared with past years. In defense of manufacturers, they make a safe product that is priced right and they are helping consumers by adjusting their product. Add your own improvement by installing a timer and scheduling hot water use. 9 ways to save with a water heater
 Larger image How to wire thermostats |
| NON-simultaneous:
Household electric
water heaters are wired for NON-simultaneous operation. Both elements are not ON at same time. Upper element is ON, or Lower element is ON, or both elements are OFF. How to wire thermostats |
 Tank must be full of water or elements burn out How to troubleshoot electric water heater Flooded water heater |
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Water
heater is steel tank, covered with insulation, and surrounded by metal
shell 1) Steel tank holds pressure of hot water. 2) Tank can be rusted and leaking. Read Leaking water heater. Read about Anode rod 3) Insulation helps prevent heat loss. 4) Metal shell protects wires from damage. 5) Any short to metal tank will trip breaker. Ground wire must be connected to water heater. Troubleshoot electric water heater |
How to wire thermostats |
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✔Thermostat
and element must be covered Cover, insulation and protector are necessary so thermostat can read correct temperature |
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Basic 240Volt water heater circuit |
