Water Heater Pilot Light Keeps Going Out in Dunedin: Thermocouples, Drafts and Gas Supply

If the pilot light keeps going out on your gas water heater, the hot water fades first and the questions follow. In homes across Dunedin, gas tank heaters often sit in garages or utility closets, where drafts and dust play a part. The pilot sits inside a safety system built to shut off gas when something looks wrong. Here is how that system works, what trips it, what you can check and when to call a pro.

How a Standing Pilot Keeps the Burner Safe

Many gas tank water heaters use a standing pilot. This is a small flame that burns all the time and lights the main burner when the water needs heat. The pilot does a second job, too. Its flame heats the tip of a thermocouple, a metal probe that turns heat into a tiny electrical current. That current powers a small electromagnet inside the gas control valve, and the magnet holds the pilot gas passage open.

When the thermocouple cools, the current drops and the magnet lets go. The valve closes and the pilot goes dark. That design stops unburned gas from flowing when there is no flame to burn it. Some newer heaters use a thermopile instead. A thermopile is a bundle of thermocouples that makes enough power to run an electronic gas control. The logic is the same: no heat at the sensor means no gas.

Worn Thermocouples, Thermopiles and Dirty Pilots

So when a pilot light keeps going out, the real question is why the sensor stopped getting enough heat. The most common answers sit right at the pilot assembly.

• Worn thermocouple: Heat and time wear down the probe, so it makes less current even with a good flame.
• Weak thermopile: On heaters with electronic controls, a tired thermopile can leave the control short on power. A status light may blink a pattern that the label explains.
• Dirty pilot orifice: Dust or lint in the tiny pilot opening makes the flame small, lazy and too weak to heat the sensor.
• Misaligned flame: If the flame does not touch the thermocouple tip, the sensor never gets hot enough.
• Clogged flame arrestor: Many newer heaters draw combustion air through a flame arrestor, a screen near the base. Lint and dust can choke that screen and starve the flame.

Drafts, Vapor Sensors and Gas Supply

Garages and utility closets move a lot of air, and a pilot flame is small enough to be pushed off its sensor. In a garage, drafts are a common reason a pilot light keeps going out. An open garage door, a gusty summer thunderstorm or a slamming closet door can all nudge the flame. A problem in the vent can also let air push down the flue toward the burner.

Many newer gas heaters also carry a flammable vapor sensor. It is designed to shut the heater down if it senses vapors from products like gasoline or solvents near the base. On many models, a tripped sensor locks the heater out, and it will not relight until the cause is found.

Gas supply matters, too. A valve left partly closed after other work, air in the line after a repair or a propane tank running low can all weaken the pilot. A small, wavering flame can look lit and still fail to heat the thermocouple.

A Dunedin Scenario You Might Recognize

Picture a family in Dunedin whose gas water heater sits in an attached garage near the lawn mower and a gas can. Showers turn lukewarm on a stormy afternoon. They relight the pilot by the label, and it holds for a day or two. Then it goes out again, usually after the garage door has stayed open during a windy storm. When they hold the pilot button, the flame looks small and a little yellow instead of crisp and blue.

That pattern points in more than one direction. The timing suggests drafts are pushing a flame that is already weak. The small, yellow flame hints at a dirty pilot orifice or a clogged flame arrestor that starves the burner of air. The gas can nearby raises a third concern, because vapors near the base can trip the flammable vapor sensor on newer heaters.

What You Can Safely Check Yourself

When the pilot light keeps going out, a few checks need no tools and no disassembly. Start by looking through the small viewing window near the base. A healthy pilot is usually a steady blue flame that wraps the tip of the thermocouple. A lazy, yellow or flickering flame is worth noting.

• Control setting: Make sure the gas control knob is set to On, not Pilot or Vacation.
• Other gas appliances: If a gas range or dryer lights normally, gas is likely reaching the house.
• Timing: Write down when the pilot goes out, such as after storms, with the garage door open or when the dryer runs.
• Status light: On electronic controls, count the blinks and compare them to the label.
• Clearance: Move gasoline, paint thinner and cleaners away from the heater, and keep lint off the floor around its base.

Relight only by following the lighting instructions printed on the heater's label, including the waiting period. If the pilot will not stay lit after that, stop and leave the rest to a professional.

Safety Notes

• Gas smell: Utilities add an odorant called mercaptan so leaks can be smelled, according to NFPA fuel gas safety guidance. If you smell gas, do not relight anything or touch switches. Get everyone outside, then call 911 or the gas utility's emergency line from outside.
• Propane homes: The same steps apply to propane, as this propane safety guidance explains.
• Carbon monoxide alarm: If a CO alarm sounds, get everyone outside and call 911 from outside. The EPA notes that carbon monoxide has no color or smell.
• Alarm placement: The NFPA recommends CO alarms outside each sleeping area and on every level of the home.
• Safety devices: Do not bypass, hold down or wedge the pilot button, thermocouple or vapor sensor to keep gas flowing.

When to Call a Professional

These fixes involve gas controls, and that work belongs to a trained professional. Call for service when:

• The pilot light keeps going out after you follow the label instructions.
• A status light or lockout shows that the flammable vapor sensor has tripped.
• You see soot, scorch marks or yellow flames around the burner door.
• The pilot goes out along with water that seems far too hot, which can point to the high-limit switch in the gas control.
• You suspect a vent problem or a draft pushing down from the flue.
• Several gas appliances seem weak at the same time.

A technician can test the thermocouple or thermopile, clean the pilot orifice and check the vent and gas supply. Hafke Plumbing offers water heater repair and replacement for gas tank heaters, and weak supply problems fall under gas line repair.

The EPA page above also passes along the CPSC's advice to have fuel-burning appliances, including water heaters, inspected by a professional every year. A routine water heater maintenance visit is a good time to have the pilot assembly and flame arrestor cleaned.

Frequently Asked Questions

Why does the pilot stay lit only while I hold the button?

Holding the button forces the gas valve open by hand. When you release it, the thermocouple has to hold the valve open on its own. If the pilot dies at that moment, the thermocouple may be worn or the flame may not be reaching its tip.

Is it safe to relight when the pilot light keeps going out?

Relighting once by the label instructions is reasonable. If it goes out again, something is causing it, and more relighting will not fix it. If you smell gas at any point, stop and get everyone outside.

Can a draft really put out a water heater pilot?

Yes. Air moving through a garage or closet can push a small flame away from the sensor, especially one already weakened by dirt or low gas supply.

Does this mean I need a new water heater?

Not necessarily. Many causes come down to parts such as the thermocouple, pilot assembly or gas control. Some vapor sensor lockouts lead to bigger decisions, and a professional can explain the options.

Your Next Step With Hafke Plumbing

Before you call, note when the pilot goes out and what was happening, such as wind, an open garage door or the dryer running. Write down the flame color, whether it stays lit while you hold the button and any status light pattern. Snap a photo of the heater's label so the model and serial number are ready.

Then contact Hafke Plumbing to schedule water heater service in Dunedin. If your pilot light keeps going out, those notes help the technician go straight to the likely cause.