At any one time, only one element will be active. This is referred to as a "flip/flop system." A 240-volt water heater will always supply 120 volts to both elements. When the tank is full with cold water, the upper thermostat takes precedence and heats the top portion of the water to the temperature specified by the thermostat. As soon as the lower thermostat reaches its setting, it turns off the lower element.
Electric space heaters use elements that are wired in parallel. This means that each element gets the same voltage from the plug but can still turn on and off independently. The control switch for these appliances usually has three positions: off, low, and high. If you leave the control out of position 2, it will still provide heat; however, if you leave it out of position 1, it will not heat at all.
The type of element used in space heaters affects how much energy they consume. High-limit heaters have two types of elements: magnetic and ceramic. Low-limit heaters have magnetic elements. Both types of elements require regular maintenance to ensure they continue to work properly. In addition, magnetic elements contain iron or steel and thus attract metal objects such as keys or loose change. These objects can short out circuit boards and cause fires.
Ceramic elements release less oxygen into the air when they are heating up than magnetic elements do so they are preferred by health officials.
Because it contains two heating components, an electric storage-tank water heater has two thermostats. The thermostats are built in such a way that only one element is operational at any one moment. The fact that just one element is active at a time allows for reduced cable diameters and lower amperage needs when in use. Storage-tank heaters were once all gas powered but now mostly use electricity instead.
Storage-tank water heaters work by storing excess heat in the form of water or steam inside a large metal tank. This heat is released through tubes located in the bottom of the tank where they contact the water. These tubes can be either aluminum or steel with aluminum being less expensive but more conductive to heat. The number and length of these tubes determines how much heat the heater can release.
Electric storage-tank water heaters work similarly to their gas-powered counterparts but instead of burning gas, they use electricity from a wall outlet. The main difference between this type of heater and others is that it can continue to produce hot water even when not used because it keeps the temperature stored within it constant. The only thing that will stop the flow of water into the tank is if the electrical power goes out which will cause the pump to shut off too.
Hot-water tanks need to be refilled periodically to keep them operating efficiently. This usually involves turning off the main valve blocking water from entering the tank and then pumping fresh water into it.
Electric water heaters often include two sets of heating elements, top and bottom, that are powered by two different thermostats. One regulates the temperature of the water at the top of the tank, while the other regulates the temperature at the bottom. This allows the water to heat up faster at the top of the tank where it is being used, but not so fast at the bottom where it would overflow the tank.
The majority of electric water heaters sold today are controlled by one-way valve circuits. This means that if the heater is on and a door or window is opened then water will rush out into the room forcing the door or window to close. When the power goes off then the valve will open again when you turn the power back on the heater will start up again but now at a lower temperature because it took time for the valve to open up again after it had closed. Some people call these heaters "one-touch" heaters because they can be turned on with one button instead of having to wait for the heat to come on by itself.
Heaters that use two-way valves work the same way as those using one-way valves except that they cannot be turned off unless the power is removed from the house. With two-way valves, if a door or window is opened when the heater is on then the valve will stay closed until you turn off the power or open the valve manually.