The Pilot Light Keeps Going Out: What It Means
You relight the pilot, it holds for a bit, and then it's out again a few hours or days later. If this cycle feels familiar, your water heater is trying to tell you something specific. A pilot light doesn't go out randomly. There's almost always a mechanical or safety-related reason behind it.
Cause 1: A faulty thermocouple
The thermocouple is a small safety sensor that sits right next to the pilot flame. Its job is to confirm the flame is actually burning, and if it senses no heat, it automatically shuts off gas flow to prevent unburned gas from leaking into your home. This is a critical safety feature, but thermocouples wear out over time, and a weakening one can misread a perfectly normal flame as "out," shutting off the gas even though everything was fine.
This is the single most common cause of a pilot light that won't stay lit, especially in water heaters more than a few years old.
Cause 2: A draft near the pilot
Pilot lights are small, and it doesn't take much airflow to snuff them out. Drafts can come from a nearby door, a window, a return air vent, or even the water heater's own vent pipe if there's a downdraft issue. If your pilot goes out inconsistently, especially on windy days or when a nearby door is open, a draft is worth ruling out before assuming a parts failure.
Cause 3: A dirty pilot orifice
The pilot orifice is a tiny opening that controls gas flow to the pilot flame. Over months and years, it can accumulate dust, debris, or mineral deposits, restricting gas flow enough that the flame burns weak and unstable, more prone to going out from minor disturbances. A weak, small, or oddly colored pilot flame (it should burn a steady blue, not yellow or orange) is a sign this might be the issue.
A quick way to narrow it down
- Relight the pilot and watch the flame color and steadiness. Weak or discolored flame points toward a dirty orifice.
- Note whether it goes out at consistent times (like when the furnace kicks on nearby) versus randomly. Consistent timing suggests a draft.
- If the flame looks normal and there's no obvious draft, but it still won't hold, the thermocouple is the most likely culprit.
Why this isn't a tinkering project
It can be tempting to just keep relighting the pilot and hope it eventually holds, but repeated gas-related issues are a safety matter, not a maintenance inconvenience. A failing thermocouple exists specifically to prevent gas from flowing when there's no flame to burn it, so a "quick fix" that bypasses or ignores that signal, rather than addressing the underlying cause, isn't a fix at all. Gas control valves and thermocouples also aren't always simple swaps depending on your specific water heater model.
If your pilot light keeps going out despite ruling out an obvious draft, or if you ever smell gas near the unit, it's time to stop relighting it yourself and have ProFlow Plumbing take a look. Gas safety components are one area where getting it exactly right matters more than getting it done quickly.