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Learn how a gas water heater works and how to maintain it.
How Do Electric Water Heaters Work?: A Technical Overview
Electric water heaters safely heat water for your home using electric heating elements and a simple control system. Understanding how your electric water heater works can empower you to maintain and troubleshoot it effectively, saving time and money while ensuring a consistent hot water supply.
In this article, we’ll explain how your electric water heater works and how to keep it working safely and efficiently for years to come.
KEY TAKEAWAYS
- Electric water heaters use insulated tanks, thermostats, and heating elements to heat and maintain water at a desired temperature, typically around 120°F. The thermostats control energy efficiency by alternating the activation of the upper and lower heating elements.
- Regular maintenance, such as annual tank flushing, testing the T&P valve, and checking the anode rod, helps prevent issues like sediment buildup, corrosion, or safety valve failure, extending the life of the water heater.
- Issues like no hot water, overheating, or tank leaks often stem from broken heating elements, malfunctioning thermostats, or internal corrosion. Understanding the water heater's functionality can aid in DIY troubleshooting or indicate when professional repair or replacement is necessary.
The Basics of Electric Water Heater Operations
An electric water heater consists of a large, insulated storage tank, usually holding between 30 and 80 gallons of water. It works by heating water using electrical energy and maintaining it at a set temperature until needed. Here's a breakdown of its key components:
- Tank: The heart of the water heater, the tank is lined with a corrosion-resistant material and surrounded by insulation to reduce heat loss.
- Cold Water Inlet and Hot Water Outlet: Cold water enters the tank through the inlet, and heated water exits through the outlet at the top of the tank.
- Dip Tube: Inside the tank, the dip tube directs incoming cold water to the bottom, where it is heated.
- Heating Elements: These electric-powered elements, typically two in number (upper and lower), heat the water directly.
- Thermostats: Each heating element is paired with a thermostat to control the temperature of the water. The thermostats cycle the elements on and off to maintain safe water temperature (around 120-degrees).
- Drain Valve: Located at the bottom of the tank, this valve is used to empty the tank for maintenance or replacement.
- Pressure Relief Valve (T&P Valve): A critical safety feature, it prevents excessive pressure buildup by releasing water if the pressure or temperature exceeds safe limits.
The Control System: Keeping the Heat in Check
The control system of an electric water heater is relatively simple but effective.
The upper thermostat primarily controls the water heater and manages the two heating elements. It ensures the upper element activates first to heat water at the top of the tank.
Once the upper section reaches the desired temperature, the lower thermostat activates the bottom element to heat the remaining water.
This sequence of heating conserves energy by not activating both elements simultaneously.
The thermostat settings are adjustable, typically ranging between 120°F and 140°F, depending on your preference and energy-saving goals.
How the Heating Elements Work
The heating elements are encased in metal and are immersed directly in the water within the tank where they convert electrical energy into heat. Here's how they function:
- Activation: When the water temperature drops below the thermostat setting, the thermostat signals the corresponding element to turn on.
- Heating Process: The element rapidly heats the surrounding water.
- Cycling: Once the water reaches the desired temperature, the thermostat cuts power to the element, preventing overheating.
The upper heating element is critical for quick access to hot water, while the lower element maintains the tank’s overall temperature.
Maintenance Tips for Long-Lasting Water Heater Performance
Regular maintenance is essential to ensure your electric water heater remains efficient and reliable. Follow these tips:
1. Flush the Tank Annually
Sediment and mineral buildup can reduce efficiency and damage the heating elements. Flush sediment from the water heater tank by following the procedure shown in this YouTube video:
Follow the steps in the video carefully to prevent damaging heating elements when refilling the water heater.
2. Test the T&P Valve
This safety valve can prevent accidents but must function correctly.
Lift the valve's lever to release water. If no water flows or it doesn’t reseal, replace the valve.
This DIY video shows how to replace the T & P valve:
3. Check the Anode Rod
The anode rod prevents rusting by attracting corrosive elements in the water.
Anode rods have a finite lifespan, typically lasting between 3 and 5 years, depending on the water quality and usage. When the anode rod is fully consumed, the corrosive elements in the water start attacking the tank itself, which can lead to leaks and, eventually, tank failure.
Check the anode rod every few years and replace the rod if it’s less than ½ inch thick or coated with calcium.
Here’s a video that shows how to replace the anode rod:
Common Water Heater Problems and Solutions
Even with proper maintenance, you may encounter occasional issues. Here's how to troubleshoot the most common water heater failures.
No Hot Water
There are a number of issues that could be to blame when your electric water heater isn't heating. You could have an issue with your power supply or a break in the wiring. One of the two heating elements could be broken, causing your hot water to run out faster than it should. Or your water heater could have a broken thermostat.
This popular YouTube video shows you how to safely check continuity on the various parts and wires inside your water heater so that you can easily fix the problem:
If you’re unable to find and fix the cause of the heating problem yourself, schedule water heater repair service and we’ll fix the water heater for you.
Water Too Hot
A water heater that overheats water can be a dangerous problem. Aside from possible burning, overheated water could be a sign of a short-circuited heating element or a malfunctioning thermostat.
This DIY troubleshooting video shows you how safely check continuity on the various parts and wires inside your water heater so that you can find the cause of the overheating problem:
If you aren’t able to find and fix the overheating problem on your own, schedule water heater repair service and we’ll send a Sears Home Services technician to your home to fix the problem for you.
Tank is Leaking
When you discover that your water tank is leaking, you’ll likely need to replace the water heater.
Shut off the house circuit breakers to disconnect electrical power and drain the tank as shown in the above video for flushing sediment from the tank.
Understanding how your water heater works will help you properly maintain it and fix problems as they occur.
With regular maintenance and attention to potential issues, your water heater can serve you efficiently for years to come. Stay proactive, and enjoy the comfort of hot water whenever you need it.
Frequently Asked Questions
How do electric water heaters generate hot water?
They use electric heating elements inside the tank to warm the water. Sears Home Services can repair and maintain these systems efficiently.
Are electric models less expensive than gas units?
They often have a lower upfront cost but may run higher operating costs depending on electricity rates. Sears Home Services can help you compare savings.
Do they require less ventilation?
Yes, electric heaters don’t need venting like gas units. Service providers can ensure proper hookup to meet local codes.
How can I extend its lifespan?
Regular maintenance like flushing sediment is key. Sears Home Services technicians can create a schedule tailored to your usage.
Schedule your water heater repair now!
Our technicians possess the knowledge and training to fix your water heater, no matter where you bought it.
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Repair Water Heater Resources
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Glossary Terms
Hard water is water that contains high levels of dissolved minerals, particularly calcium and magnesium. It contrasts with soft water, which has lower concentrations of these minerals.
A thermocouple is a sensor used for measuring temperature, consisting of two different metal wires joined at one end, which generate a voltage proportional to temperature changes.
A K-type thermocouple is a sensor used for temperature measurement, consisting of two dissimilar metal wires that generate a voltage proportional to temperature changes, widely recognized for its accuracy and wide temperature range.
A heat pump water heater is an energy-efficient appliance that uses electricity to move heat from the air or ground into water, rather than generating heat directly.
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