HOW ELECTRIC HOT WATER HEATERS ARE WIRED

 

 

hot water heater wiring

Black and White wires are hot. A bare copper is the ground.

In some installations, all the incoming wires may be of the same color so the use of a test meter is recommended.

Diagram 2:    4-WIRE, 208/240 VOLT CIRCUIT WITH NEUTRAL WIRE.

(Not typically found in residential water heater circuits)

 digagram 2

Black and Red wires are hot. Bare copper is ground. White is neutral.

 In some installations, all the incoming wires may be of the same color so the use of a test meter is recommended.

HOW AN ELECTRIC HOT WATER HEATER WORKS

water heater works

  How an electric hot water heater works

New water heater. Cold water inside tank. (Image 1). When hot water faucet is turned on, hot water immediately leaves the top of the tank. Hot water travels through pipes until it reaches a faucet. At same time, new cold water enters bottom of tank through dip tube pipe. (Image 6).

When there is demand for hot water, the exiting of the hot water and the entry of replacement cold water, causes the  activatation of the heating element. Tanks have 1 or 2 elements, depending on design.

(See image 1 for element/thermostat location).

Heating 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 a 2-element tank, if the 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.

Image 1 shows a tank with 2 heating elements called upper and lower elements. Elements are controlled by upper and lower thermostats. Thermostats read temperatures from the 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. Both elements are never ON at same time unless specific wiring is changed.

The upper thermostat is main controller. It turns on the upper element until the top 1/2 of tank reaches the on-board temperature setting. (See image 2). After that, the upper thermostat turns-off the upper element and sends power to lower thermostat which turns on the lower element. (See image 3). The lower element runs until tank reaches the temperature setting. During ‘standby’, between hot water use, the lower element maintains tank temperature. (See images 4 & 5).

The lower element keeps the water hot by turning on 3-4 minutes each hour throughout day and night which equals 126 kWh – 216 kWh each month for standby operation depending on tank rating and seasonal temperature. Once hot water is used again, cold water quickly fills tank and elements are activated and heating cycle repeats.

ADJUSTING ELECTRIC HOT WATER HEATER THERMOSTATS

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STEP 1: 

*FOR SAFETY, TURN OFF POWER AT THE BREAKER PANEL*

STEP 2:

Remove access covers at top and bottom of water heater

(save the screws)

Pull out insulation covering the thermostats.

NOTE:

Top thermostat is larger, Bottom thermostat is smaller

*Don’t touch or move wires.

*Insulation & covers must be put back when finished or thermostats will not read the temperatures correctly.

 UPPER/LOWER THERMOSTATS:

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STEP 3:

Using a straight blade screwdriver, set the top and bottom thermostats to 120°. This temperature is good for most homes.

For homes that use/require more hot water, set top thermostat 5-10° higher.

All water heater thermostat settings are approximate. Test actual water temperature at a faucet with a thermometer.

STEP 4:

After completing the thermostat adjustments, replace the insulation pieces making sure to cover the thermostats so that cool air will not cause the thermostats to misread temperatures.

Replace the access covers screws previously removed.

*DON’T FORGET TO RETURN THE BREAKER TO THE ON POSITION FOLLOWING THE MAKING OF THESE ADJUSTMENTS*

 

HOW MUCH DOES IT COST TO OPERATE AN ELECTRIC HOT WATER HEATER?

 

OPERATING PARAMETERS:

3 hours is approximate daily run-time for water heater, depending on usage and the temperature of incoming water supply.

The colder the incoming water supply, the longer it will take to heat the tank to 120°.

FYI: A Bath uses 12-15 Gallons of hot water.  A Shower uses 5-9 Gallons of hot water.

To calculate water heater operating costs, first determine the wattage of the water heater.

 

 WATER HEATER WATTAGE LABEL LOCATION

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Water Heater Wattage can be Found on the Label on the side of Water Heater:

Water heaters with 2 elements are 240Volt

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1 Phase or single-phase is household electric service 240 Volts

Two 5500 Watt elements.
Total connected 5500 watts.

When water heater has 2 elements and both elements are 5500, then overall tank Wattage is 5500.
Both elements are never turned on at same time.
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If water heater operates 3 hours per day, then the monthly kWh usage per month is calculated at:
5500 Watt  = 495 kWh per month
4500 Watt  = 405 kWh per month
3500 Watt  = 315 kWh per month
1500 Watt  = 135 kWh per month

Example:
5500 Watts x 3 hours = 16,500 watt-hours or 16.5 kWh per day.
For a full 30-day month: 30 days x 16.5 Kwh per day = 495 kWh per month for water heater electricity
Calculate cost per month: 495 kWh x $.10 per Kwh = $49.50 + taxes.

3 hours a day @ 10¢ per kWh
5500 Watt tank = $49.50 per month
4500 Watt tank = $40.50 per month
3500 Watt tank = $31.50 per month
1500 Watt tank = $13.50 per month

3 hours a day @ 12¢ per kWh
5500 Watt tank = $59.40 per month
4500 Watt tank = $48.60 per month
3500 Watt tank = $37.80 per month
1500 Watt tank = $16.20 per month

3 hours a day @ 14¢ per kWh
5500 Watt tank = $69.30 per month
4500 Watt tank = $56.70 per month
3500 Watt tank = $44.10 per month
1500 Watt tank = $18.90 per month

3 hours a day @ $.16 per Kwh
5500 Watt tank = $79.20 per month
4500 Watt tank = $64.80 per month
3500 Watt tank = $50.40 per month
1500 Watt tank = $21.60 per month

3 hours a day @ $.20 per kWh 
5500 Watt tank = $99.00 per month
4500 Watt tank = $81.00 per month
3500 Watt tank = $63.00 per month
1500 Watt tank = $27.00 per month