A pilot light that dies once may just be a draft. One that dies every few days is telling you something is wrong.
Most of the time it's a worn thermocouple or a dirty pilot tube. Sometimes it's the vent. That one is a safety problem, not a comfort problem.
A worn thermocouple is the most common cause
The thermocouple is a thin metal rod that sits in the pilot flame. The heat makes a tiny electric current.
That current holds the gas valve open. No flame means no current, and the valve shuts. It's a safety design, and it works.
The rod wears out over the years and gets weak. It can also sit just outside the flame after a bump or a cleaning.
Once it's weak, the valve reads the flame as gone and cuts the gas. The pilot dies while you stand there watching it burn.
You can often spot a bad rod by eye. The tip looks pitted or burned, and the nut at the valve may be loose or sooty.
A thermocouple is a low cost part. Swapping one is a short visit on most tank heaters.
A dirty pilot tube starves the flame
Dust, lint, spider webs, and rust flakes collect in the small pilot tube. Garages in Phoenix are dusty places.
A tube that's partly blocked gives you a weak yellow flame instead of a strong blue one.
That weak flame can't keep the rod hot enough, so the valve closes again.
Look at the flame before you do anything else. A healthy pilot is blue, steady, and wraps the tip of the rod.
Cleaning the tube and its orifice is routine work. It starts with shutting the gas off at the heater.
Gas supply and valve trouble show a pattern
If the pilot lights and dies within seconds every single time, look at gas delivery.
A shutoff left part way closed, a kinked flex line, a stuck regulator, or low supply pressure will all starve the flame.
If a furnace or a range in the same home acts up too, the trouble is upstream of the heater.
Gas control valves fail as well, though less often than a thermocouple does. Some heaters also have a thermal switch under the burner that trips and locks the unit out.
Note the timing before you call. Seconds, minutes, or days between failures each point at a different part.
That switch trips for a reason. Resetting it without finding the cause is how a small problem turns into a big one.
Drafts and venting can be a safety problem
A gas heater has to push its exhaust up the vent and out of the house. That exhaust carries carbon monoxide.
When the vent is blocked, loose, or rusted through, exhaust can spill back into the room. That's called backdrafting.
Backdrafting can blow out a pilot. It can also put carbon monoxide where you breathe, and you can't smell it.
Garages bring their own risk. Gas fumes from a car or a can settle low, so the burner has to sit up off the floor or be a sealed design.
A strong draft alone can kill a pilot as well. A door propped open near the heater or a burner cover that doesn't seal will do it.
Stop and get help right away if you see any of this:
- Soot or scorch marks around the top of the heater
- A vent pipe that's loose, rusted through, crushed, or disconnected
- A sharp or burning smell in the room while the burner runs
- Headaches, dizziness, or nausea that ease once you step outside
- A carbon monoxide alarm going off
Stop relighting the pilot after the second try
If you smell gas, don't touch a switch or a lighter. Leave the house, then call your gas company from outside.
Every home with a gas appliance needs a working carbon monoxide alarm. Put one near the bedrooms and test it.
Relighting a pilot once is fine. Doing it again and again is not. Each try puts more gas in the burner area and hides a fault you should be fixing.
Call a licensed plumber if the pilot won't stay lit after two tries. Do the same if the flame is yellow and lazy, or if the vent looks wrong.
Age counts too. If the tank is past 10 years and rusting or leaking at the base, repairs stop making sense.
Get the heater checked before your next cold shower
We check the thermocouple, the pilot assembly, the gas supply, and the vent on the same visit. You get the cause, not a guess.
Most pilot problems are fixed the same day, and the estimate is free. If the tank is finished, we'll show you why.
Warriors Plumbing & Rooter is licensed under Arizona ROC #352091 and answers the phone at any hour.
Call (602) 743-9591 and we'll get your hot water back.
