Having hot water available at all times is something most homeowners take for granted. So when a water heater suddenly stops working and fails to ignite, it can be frustrating and confusing. There are several potential causes for a water heater ignition failure, ranging from simple fixes to more complex underlying issues. Getting to the root of the problem quickly is important to restore hot water availability in your home.
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Main Causes of Water Heater Ignition Failure
There are a few common reasons why a gas or electric water heater will not ignite:
- Pilot light is out or malfunctioning
- Gas line issues such as leaks, blockages or insufficient pressure
- Problems with thermocouple or thermopile sensor
- Faulty gas valve or control
- Insufficient air intake
- Corroded or dirty burners
- Blown fuse or tripped circuit breaker
- Heating element failure
Identifying the specific problem is the first step toward getting your hot water heater running again. In many cases, the issue may be simple and repairing it yourself is possible. However, serious problems can arise if certain ignition failures are not properly diagnosed and addressed.
Gas Water Heater Ignition Problems
For gas-powered water heaters, issues with the pilot light are one of the most common reasons for ignition failure. The pilot light is a small flame that ignites the burner when hot water is needed. If the pilot light goes out, the main burner cannot turn on. A pilot light may go out if it runs out of gas, gets blocked by dirt or debris, the flame sensor fails, or high winds blow it out.
Gas line problems can also prevent ignition. A gas leak, kink in the line, or insufficient gas pressure to the unit will mean gas cannot properly reach the pilot or burner for ignition. The control valve and thermocouple or thermopile sensor are other key components that may malfunction and prevent gas ignition.
Insufficient air supply is another potential issue if the burner flames are being deprived of oxygen. The burner may struggle to light or the flame may be unstable or too low. Finally, the burners themselves may have corroded or collected dirt over time leading to clogs and ignition problems.
How to Troubleshoot Gas Water Heater Ignition
Start by checking the pilot light. Locate the small flame inside the main burner compartment. If it is out, refer to the owner’s manual for proper relighting technique. Make sure gas is on and bleed all air from the gas line first. If the flame lights but keeps going out, the issue may be with the flame sensor and a repair or replacement may be needed.
Inspect the gas line and valves for leaks. Use soapy water to spot leaks which will bubble up. Tighten fittings or replace pipes as needed. Check supply pressure to verify adequate gas is coming into the heater. Clean burner tubes and orifices if excess debris is present.
Test components like the thermocouple, thermopile and gas control valve for proper operation. These parts may need cleaning or adjustment. If problems persist, replacement of part or entire gas control assembly may be required.
Electric Water Heater Ignition Failure
Electric water heaters rely on heating elements to heat the water. If the elements fail to engage and heat up, the unit will not function. Fuse box issues like a blown fuse or tripped breaker are one cause of electric ignition problems. Insufficient voltage to the unit can also prevent the elements from working properly.
Mineral deposits and sediment collecting on the elements over time can lead to element failure. While less common, damage to internal wiring from rodents or corrosion is another potential source of ignition issues.
Fixing Electric Heater Ignition
Checking the home’s electrical service panel is the first step in diagnosing electric heater problems. Reset any tripped breakers and replace blown fuses. Verify the heater is getting the correct 240V supply. Test heating elements using a multimeter to determine if they are burned out and need replacement.
Inspect all wiring for damage and test components like sensors and thermostats. Flush heating elements to remove any mineral deposits. If internal wiring is damaged, replacement of heating elements or entire upper heating assembly may be needed.
Other Causes of Water Heater Problems
While ignition or heating element failures are the most direct causes of a water heater not heating, there can be other contributing factors:
- Sediment buildup in tank
- Draining and refilling tank
- High water pressure
- Thermostat or temperature settings
Heavy lime and mineral deposits in the tank can lead to hot spots and cause burnout of elements. Draining the tank, including to perform maintenance, also introduces air which can interfere with ignition. Excess water pressure can damage components like valves, reducing their lifespan.
Ensure the thermostat is properly calibrated and set to the desired temperature. Setting it too high can increase risk of sediment buildup. Checking these other conditions can help get to the root cause of ignition problems.
When to Call a Professional
For serious or complex water heater problems, it is best to call a professional plumber or appliance repair technician:
- Persistent pilot light or ignition failure
- Leaking or damaged gas lines and valves
- Electrical issues at the fuse box or with unit wiring
- Thermocouple/thermopile defects
- Damage or failure of heating elements
- Component replacement needed
- Unit is over 10-15 years old
While do-it-yourself repairs can solve simple issues, a technician has the skills to properly diagnose and fix or replace internal components of gas and electric water heaters. They can ensure any gas leaks or electrical problems are safely handled.
How Much Does Water Heater Repair Cost?
The cost to repair a water heater ignition problem can range from $100 to over $500 depending on the specific issue and parts needed. Some average repair costs include:
- Pilot light or thermocouple repair – $120-$250
- Gas valve replacement – $225-$350
- Heating element replacement – $150-$300
- Thermostat replacement – $125-$225
- Full gas control unit replacement – $400-$600
Labor will account for a significant portion of the total bill as well. More complex repairs requiring full component replacement will be toward the higher end of the price range.
Factors That Affect Water Heater Repair Cost
- Age and type of water heater
- Labor hourly rates
- Extent of repairs needed
- Heater fuel source (gas vs electric)
- Brand and model of unit
- Local repair costs
Modern tankless water heaters tend to be more expensive to service than traditional tank heaters. Gas heater repairs often cost more than basic electric repairs. Parts for premium brands can be pricier as well. In general, more repairs and longer labor time increase overall cost.
Preventing Water Heater Ignition Problems
With proper care and maintenance, you can minimize problems with water heater ignition failure:
- Have a technician inspect and service the unit annually
- Change out heating elements every 5-8 years
- Flush mineral deposits from tank
- Clear debris around pilot light and burners
- Fix any gas or water leaks promptly
- Keep supply valves in working order
- Replace gas control assembly if over 10 years old
Routine professional service can catch issues before they escalate. Replacing worn parts and maintaining a clean, leak-free unit improves the lifespan. Review the manufacturer’s maintenance guidelines as well.
Conclusion
Water heater ignition or heating failures can have various causes ranging from pilot light problems to heating element defects. For gas heaters, the thermocouple, gas valve and burners are common points of failure. Electric models more often have thermostat, fuse and heating element issues. While some problems are minor, it’s best to have a technician inspect the unit for proper diagnosis and safety.