Electric water heaters are convenient appliances that can provide hot water on demand for your home. However, like any appliance, they can develop issues over time that require troubleshooting and repairs. With some basic mechanical skills and electrical knowledge, many problems with electric water heaters can be diagnosed and fixed by homeowners.
Safety Precautions When Working on an Electric Water Heater
When troubleshooting or repairing an electric water heater, it’s important to take proper safety precautions:
- Turn off the power supply to the water heater at the circuit breaker before doing any work. Verify power is off by testing with a non-contact voltage tester.
- Allow the water heater to fully cool if it has recently been heating water. The tank surfaces can reach dangerously high temperatures.
- Have a fire extinguisher on hand in case of electrical fires. Class C extinguishers designed for electrical fires are ideal.
- Wear insulated gloves and use insulated tools when testing or replacing electrical components.
- Keep the area around the water heater dry to avoid electrocution hazards.
- Have another person present in case an emergency occurs.
- Follow all manufacturer safety warnings and instructions.
Taking these precautions will help avoid serious injuries like burns, shocks, or electrocution when working on an electric water heater.
Troubleshooting Common Electric Water Heater Problems
Here are some of the most frequent issues that can arise with electric water heaters and how to diagnose them:
Problem: Water is Not Hot Enough
- Cause: Thermostat is set too low
- Solution: Adjust thermostat to a higher temperature
- Cause: Element failure
- Solution: Test element with a multimeter and replace if defective
- Cause: Sediment buildup
- Solution: Flush tank and heating elements
Problem: No Hot Water
- Cause: No power to heater
- Solution: Check circuit breaker and wiring connections
- Cause: Failed thermostat
- Solution: Test thermostat and replace if needed
- Cause: Both heating elements not working
- Solution: Test elements with multimeter and replace any defective ones
Problem: Water Not Heating At All
- Cause: Timer or thermostat is defective
- Solution: Test and replace defective components
- Cause: High-limit safety switch tripped
- Solution: Reset switch; determine cause of overheating
- Cause: Wiring issue
- Solution: Check all wiring connections
Problem: Water Heater Leaking
- Cause: Leak from a plumbing connection
- Solution: Tighten or replace leaking fitting
- Cause: Leaking anode rod
- Solution: Replace leaking anode rod
- Cause: Leaking tank
- Solution: Tank is failing; water heater will need replacement
Problem: Burning Smell or Scorched Outlet
- Cause: Overheating element
- Solution: Test elements and replace any defective ones
- Cause: Electrical short
- Solution: Inspect all wiring for damage or shorts
- Cause: Thermostat issue
- Solution: Replace thermostat
Knowing the most common issues and their causes can help quickly diagnose problems with an electric water heater.
How to Test an Electric Water Heater Element with a Multimeter
One of the most likely parts to fail on an electric water heater is the heating element. To test if the element is defective, you will need a multimeter set to the ohms setting. Follow these steps:
- Turn off power to the water heater at the circuit breaker.
- Drain the tank until water level is below the element.
- Remove the access panel over the element.
- Disconnect the wiring to the element.
- Set a multimeter to the ohms setting, usually indicated by the Greek omega (Ω) symbol.
- Touch the multimeter probes to the element terminals. A good element will have a very low resistance, usually between 5-25 ohms.
- If the resistance reading is infinity or a very high number, the element is likely defective and needs to be replaced.
- For complete confirmation, repeat the test on the second heating element if there is one.
This is the best method for determining if a water heater element is burned out or functioning properly. Be sure power is off for safety when testing elements.
How to Replace an Electric Water Heater Element
Replacing a defective electric water heater element is a straightforward repair that can be completed with a few tools and proper safety precautions. Follow these steps:
Supplies Needed
- Replacement element kit compatible with your heater
- Adjustable wrench
- Channel lock pliers
- Wire cutters/strippers
- Electrical tape
Procedure
- Turn off power to water heater at breaker.
- Turn off cold water supply valve.
- Attach a garden hose to the drain valve and route it to a drain or outside.
- Open a hot water faucet in the house.
- Open drain valve completely until tank is empty.
- Disconnect wiring to bad element and remove it with wrench.
- Clean threads in tank opening with rag. Apply joint compound to threads on new element.
- Screw in new element using wrench and tighten securely.
- Reconnect wires to element terminals. Make sure connections are tight.
- Fill tank by turning cold water supply back on. Check for leaks.
- Turn power back on and allow tank to fully heat up.
- Test operation and element by running hot water.
Be extremely cautious when working with electrical and water connections. Having the proper materials and following safety procedures will allow you to successfully replace a defective electric water heater element.
How to Flush and Drain a Water Heater Tank
Sediment buildup and corrosion inside the tank can reduce the efficiency of an electric water heater. Flushing the tank helps remove these deposits.
Follow these steps to flush and drain an electric water heater:
Supplies Needed
- Garden hose
- Bucket
- Water heater drain pan (optional)
Procedure
- Turn off power to water heater at breaker.
- Turn off cold water supply valve.
- Connect garden hose to drain valve at bottom of tank.
- Route hose to an outside area or into a bucket.
- Open a hot water faucet inside the house.
- Open drain valve completely until water starts flowing out hose.
- When water slows to a trickle, close drain valve.
- Open cold water supply to refill tank. Repeat flushing process.
- Once tank is refilled, turn power back on.
Flushing the tank annually can help maximize efficiency and lifespan of an electric water heater. Perform this maintenance when sediment appears in the hot water.
Resetting the High-Limit Switch on an Electric Water Heater
Electric water heaters have a high-limit safety switch that shuts off power if the tank overheats. If the switch is tripped, the water heater will not heat. Resetting this switch is easy:
Procedure
- Turn off power to water heater.
- Remove outer cover panel to access limit switch.
- Press reset button on switch until an audible click is heard.
- Replace outer cover panel.
- Turn power back on and test water heater operation.
The high-limit switch is a safety device to prevent dangerous overheating issues. If it repeatedly trips, there is likely an underlying problem causing abnormal heating that needs to be diagnosed.
How to Replace an Electric Water Heater Thermostat
If an electric water heater is not heating properly, the thermostat is often the culprit. Replacing the thermostat is an intermediate level repair:
Supplies Needed
- Replacement thermostat specific to water heater model
- Hand tools for cover panel removal
- Wire cutters/strippers
- Electrical tape
Procedure
- Turn off power to water heater.
- Drain tank until water level is below thermostat.
- Remove outer cover panel.
- Disconnect and label wires from old thermostat.
- Unscrew thermostat sensor from tank.
- Clean thermostat opening surface with steel wool or emery cloth.
- Apply thread seal tape to threads of new thermostat.
- Install new thermostat and snugly tighten.
- Reconnect wires according to wiring diagram.
- Secure wires with electrical tape.
- Refill tank and turn power back on.
- Allow tank to fully reheat and test new thermostat.
Be extremely careful working with electrical connections and draining hot water. Having the proper materials and following instructions will allow you to successfully replace a faulty electric water heater thermostat.
Troubleshooting Electric Water Heater Thermostats
If an electric heater is not heating properly, the thermostat may be malfunctioning. Here are steps for troubleshooting common thermostat issues:
Problem: Water is Lukewarm, But Thermostat is Set High
- Cause: Bad upper thermostat
- Solution: Test upper thermostat with multimeter. Replace if defective.
Problem: Water is Cold, But Thermostat is Set High
- Cause: Failed lower thermostat
- Solution: Test lower thermostat with multimeter. Replace if defective.
Problem: Water temperature fluctuates wildly
- Cause: Defective thermostat
- Solution: Replace thermostat.
Problem: Water is overheating
- Cause: Thermostat set too high or stuck closed
- Solution: Test thermostat and adjust temperature setting or replace
Using a multimeter to check thermostats and replacing defective ones can often resolve heating problems with electric water heaters.
How to Replace an Electric Water Heater Anode Rod
The anode rod in an electric water heater sacrifices itself to prevent tank corrosion. Over time it will need to be replaced. Here are the steps:
Supplies Needed
- Proper anode rod for water heater model
- Adjustable wrench
- Pipe tape
- Petroleum jelly (optional)
Procedure
- Turn off power and water supply to water heater.
- Attach garden hose to drain valve and route to drain.
- Open drain valve and hot water faucet to drain tank completely.
- Remove old anode rod with wrench. You may need to break it free by tapping with hammer if corroded.
- Apply pipe tape to threads of new anode rod.
- Rub petroleum jelly on rod threads to ease insertion (optional).
- Screw new anode rod in by hand until tight.
- Close drain valve and turn water supply back on to refill tank.
- Turn power back on once tank is full.
Inspecting the anode rod yearly and replacing as needed can prolong the life an electric water heater. This prevents corrosion damage to the inner tank.
When to Call for Electric Water Heater Repair Help
While many electric water heater repairs can be completed by a knowledgeable DIYer, there are some issues that require professional assistance:
- Leaking Tanks – If the steel tank itself is leaking, the entire water heater will need replacement. Leaking tanks cannot be safely repaired.
- Wiring Problems – Faulty internal wiring or connections should be repaired by an experienced electrician to prevent fire hazards or electrocution.
- Thermostat Replacement on Newer Heat Pump Water Heaters – The integrated thermostats on newer heat pump water heater models require specialized programming only a technician can perform correctly.
- Repeated High-Limit Switch Tripping – If the high-limit safety switch keeps tripping, there is likely an underlying problem needing diagnosis by a professional.
- Issues Requiring Tank Disassembly – Any repairs needing major disassembly of the water heater tanks should be left to qualified appliance repair technicians.
For complicated repairs or any situation where you are uncertain how to safely proceed, calling a professional plumber or appliance repair service is advisable.
When to Replace an Electric Water Heater
As electric water heaters age, repairs may no longer be cost-effective compared to replacement. Here are some typical signs indicating replacement is needed:
- Leaking Tank – Once an electric heater’s tank starts leaking, it needs to be replaced. Attempted repairs will not be effective.
- Heavily Corroded Elements – If mineral scale has built up heavily on elements, they become far less efficient. Replacement may be better than trying to remove heavy corrosion.
- Old Age – Heat pump water heaters in particular should be replaced after 8-10 years. Standard electric heaters usually last 10-15 years.
- Inability to Maintain Temperature – If you are constantly struggling to keep the water at an adequate temperature, the heater may be worn out.
- Extensive Sediment Buildup – Large amounts of sediment clogging the tank reduces efficiency considerably. Replacement may be better than trying to flush it all out.
- Major Rust or Corrosion – Pervasive corrosion damage to internal components can make repairs pointless.
- Cost of Repairs Exceeds Half the Cost of New Heater – Once repair costs start mounting, replacement becomes the better investment.
Carefully consider repair costs and water heater age when determining whether replacement is the wisest option.
Conclusion
Electric water heaters provide reliable hot water for households when properly maintained. Learning to identify common problems and perform minor repairs can save homeowners money on service calls. However, you should always take proper safety precautions when working on electrical appliances and call in professionals when needed. With routine maintenance and attention when problems arise, an electric heater can provide many years of reliable service.
Frequently Asked Questions About Troubleshooting Electric Water Heaters
Electric water heaters are cost-effective and relatively trouble-free. However, issues can arise that require repairs. Here are answers to some frequently asked questions about diagnosing and fixing common electric water heater problems.
Why does my electric water heater trip the high-limit switch repeatedly?
If an electric water heater’s high-limit safety switch keeps tripping, there is likely an underlying problem causing the tank to overheat. Potential causes include:
- Defective thermostat not regulating temperature properly
- Stuck closed or welded contacts on thermostat
- Miswired thermostat
- Sediment buildup causing insulation of heating elements
- Undersized elements leading to slow recovery time
- Incoming water temperature is already hot
A technician will need to diagnose the specific problem. Repeated high-limit switch tripping should not be ignored.
What causes the “burning” or “rotten egg” smell from my electric water heater?
An unpleasant “rotten egg” odor coming from a water heater is usually caused by bacteria growing in the tank and pipes, resulting in hydrogen sulfide gas. This bacteria growth can occur when the temperature is set too low or sediment has accumulated. Flushing the water heater tank and turning up the thermostat temperature can help eliminate the bacteria and odor. If the smell persists, the anode rod may need replacement.
Why does my electric water heater make rumbling or whistling noises?
Strange rumbling, whistling or “singing” noises from an electric heater are typically caused by sediment accumulation in the tank. As water is heated, air pockets trapped in the sediment can vibrate and resonate. Draining and flushing the tank to remove built-up sediment should quiet the noises. Loud banging or cracking noises may indicate a more serious problem with expansion or a failing tank.
My electric water heater light is blinking – what does this mean?
A blinking or flashing indicator light on an electric water heater control means the unit is displaying an error code. The specific error will depend on the number of flashes. Refer to the manufacturer’s troubleshooting guide to determine what each code signifies. Common issues indicated by a flashing electric water heater light include high-limit switch trip, bad thermostat, or faulty temperature sensor.
What causes electric water heater elements to fail?
The most common causes of electric water heating elements failing include:
- Sediment buildup leading to insulation of the element
- High levels of mineral content in water corroding the element
- Fluctuating voltage levels causing overheating
- Old age – elements may simply wear out after 5-10 years
- Improper element wattage for tank size
- Defective thermostat causing element overheating
Replacement heating elements must match the original wattage and voltage specifications for proper operation and safety.
Is it worth fixing my 10 year old electric water heater or just replacing it?
Once an electric water heater reaches about 10 years old, replacement often makes more financial sense than repairing issues. Labor and parts to fix an aging unit may run over half the cost of a new energy efficient heater. Older heaters also tend to develop more problems. Unless it’s a very minor fix, replacement is probably the wisest choice for a water heater over 10 years old.
Conclusion
Diagnosing and repairing problems with electric water heaters is made safer and easier when you understand common issues and solutions. Knowing when to call a professional is also important. With proper maintenance and attention when problems arise, an electric heater can provide reliable hot water for many years. Carefully considering when replacement is the best option can maximize cost-effectiveness.