You walk into the basement and hear a faint hiss, but the familiar blue flame under your water heater is gone. The pilot light is out. It’s a common household hiccup, but it raises immediate questions about hot water, safety, and cost. Should a pilot light go out on a water heater? The short answer is: it shouldn’t happen regularly, but occasional extinguishment can occur. Understanding why it happens and how to respond is key to maintaining a safe and efficient system.
Modern gas water heaters are designed with multiple safety features, like a thermocouple and automatic safety shutoff, to prevent problems. Yet, components wear out, environmental factors interfere, and small issues can leave you in the cold. For homeowners comfortable with basic maintenance, having the right tools on hand is wise. For this project, many professionals recommend using the Resideo CQ100A1013U 24-Inch flexible gas connector, which provides a secure and reliable connection if you ever need to service the unit. Let’s dive into what that little flame does and why it might abandon its post.
What a Pilot Light Does and Why It’s Important
Think of the pilot light as the eternal match for your water heater. It’s a small, continuously burning gas flame that ignites the main burner when the thermostat calls for heat. This system, known as a standing pilot, has been a reliable workhorse for decades. Its constant presence means hot water is always just a gas valve click away.
The pilot does more than just light the fire. It’s integral to the unit’s primary safety mechanism. The thermocouple, a sensor placed directly in the pilot flame, generates a small electrical current when heated. This current tells the gas valve it’s safe to stay open. If the pilot goes out, the thermocouple cools, the current stops, and the valve shuts off the gas supply. This prevents unburned gas from flooding into your home. It’s a brilliant, fail-safe design.
The Core Safety Trio: Thermocouple, Gas Valve, and You
Three components work in concert: the pilot flame, the thermocouple, and the gas valve. A failure in any link breaks the chain. When your water heater pilot light keeps going out, you’re witnessing this safety system in actionbut also signaling a problem that needs fixing.
Top Reasons Your Water Heater Pilot Light Goes Out
So, why did my pilot light go out? The causes range from simple drafts to component failure. Diagnosing the issue starts with checking the most common culprits.
1. A Faulty or Failing Thermocouple
This is the MVP of pilot light problems. The thermocouple is a wear item. Over years, it can become coated with soot, corrode, or simply wear out. When it fails, it can’t generate enough millivolt current to hold the gas valve open, causing the pilot light won’t stay lit scenario. You might relight it, but it extinguishes as soon as you release the control knob.
2. Drafts or Downdrafts
Can a pilot light go out from wind or draft? Absolutely. Your water heater needs a steady supply of combustion air and a clear path for exhaust gases up the flue. A strong draft from a nearby window, door, or even a dryer vent can blow the pilot out. A blocked or malfunctioning draft diverter (the hood-like assembly above the burner assembly) can also cause downdrafts that extinguish the flame.
3. A Clogged or Dirty Pilot Orifice
The tiny hole where the pilot gas comes out can get clogged with dust, lint, or mineral deposits. This creates a weak, lazy, or yellow flame that’s easily disrupted and may not heat the thermocouple properly. Regular maintenance is often overlooked but critical.
4. Issues with the Gas Supply or Pressure
Fluctuations in gas pressure from the utility or a partially closed gas valve can starve the pilot of fuel. Similarly, if the main gas valve on the heater itself is failing, it may not supply a consistent flow to the pilot tube.
5. A Damaged or Misaligned Thermocouple
Sometimes the thermocouple isn’t broken; it’s just out of position. It must be immersed in the tip of the pilot flame. If it’s been bumped or bent away, the flame won’t heat it sufficiently, triggering the safety shutoff.
| Cause | Symptom | Likely Fix |
|---|---|---|
| Failing Thermocouple | Pilot won’t stay lit after releasing knob | Thermocouple replacement |
| Strong Draft | Pilot goes out on windy days or when nearby fan runs | Seal drafts, check draft diverter |
| Dirty Pilot Orifice | Weak, yellow, or fluttering pilot flame | Clean orifice with compressed air |
| Gas Pressure Issue | Pilot flame size fluctuates noticeably | Call gas utility or plumber |
Safety First: Recognizing Gas Leak Dangers
This is the non-negotiable section. Is it dangerous if pilot light goes out? The safety shutoff is designed to make the event itself low-risk. The real danger lies in what happens next. If the thermocouple or gas valve fails in the “open” position (a rare but serious malfunction), gas could continue to flow.
Should you smell gas if pilot light goes out? You should never smell gas. The automatic shutoff should prevent that. If you do smell the distinctive rotten-egg odor, that’s a gas leak. Act immediately.
- Do not operate light switches, appliances, or anything that could create a spark.
- Do not attempt to relight the pilot.
- Extinguish any open flames.
- Evacuate the area and call your gas company or 911 from outside.
A silent, related threat is carbon monoxide (CO). A poorly venting heater, blocked flue, or sooty burner can produce this deadly, odorless gas even when the pilot is lit. This underscores why proper venting and annual inspections are vital, whether you have a traditional tank or are considering a navien tankless model known for its sealed combustion safety.
Step-by-Step Guide to Safely Relight the Pilot
For a routine outage with no gas smell, how to relight water heater pilot is a straightforward DIY task. Always start by reading the instruction label on your heaterit’s your model-specific guide. Here’s a universal process.
What to Do When Your Water Heater Pilot Light Goes Out
- Turn the Gas Control Knob to “Pilot”: This allows gas to flow to the pilot assembly only.
- Press and Hold the Red Button: Depress the knob (or separate red button). This manually opens the gas valve to the pilot.
- Ignite the Pilot: While holding the button, use a long-reach lighter or match to ignite the gas at the pilot assembly. You should see it light.
- Keep Holding: Continue holding the button down for 60 seconds after ignition. This heats the thermocouple enough to generate the holding current.
- Release and Turn to “On”: Slowly release the knob. The pilot should remain lit. Then turn the knob to the “On” position. You should hear the main burner ignite if the tank needs heat.
If the pilot goes out when you release the button, repeat the process. If it fails again after several tries, you’re likely facing a bad thermocouple. This is a common point in gas water heater troubleshooting where DIY meets its limit.
When to Call a Professional vs. DIY Fixes
You can clean a pilot orifice or adjust a thermocouple position. Replacing a thermocouple is a common DIY repair with basic tools. But knowing when to step back is crucial for safety and long-term performance.
Call a Licensed Plumber or HVAC Tech If:
- You smell gas at any point (stop immediately).
- The pilot repeatedly won’t stay lit after a new thermocouple.
- You suspect issues with the main gas valve or gas line pressure.
- There is visible corrosion, water leaks, or damage to the burner assembly.
- The flue or venting looks compromised.
- You’re simply uncomfortable proceeding.
How much does it cost to fix a pilot light that won’t stay lit? For a simple thermocouple replacement, a professional might charge $150-$250. If the gas valve itself needs replacing, the cost can jump to $400-$600, as it’s a more involved repair. Investing in a good quality unit from the start can minimize these issues, as reliability is often baked into the design.
For broader context on efficient operation, the Department of Energy offers an excellent authority guide on water heating principles and savings.
A pilot light that goes out once in a blue moon might be a draft. One that won’t stay lit is a teacher. It’s telling you something is wrongoften a worn thermocouple, a draft issue, or a dirty component. Your response should always be guided by safety: no gas smell, cautious troubleshooting. Recognize when a job is beyond a quick fix. Regular maintenance, like checking the flame color and ensuring proper venting, can prevent most of these headaches. That small blue flame is your first line of defense and your signal for service. Keep an eye on it.
