Why Does the Pilot Light on My Water Heater Keep Going Out?
A pilot light that won't stay lit is almost always one of three things: a failing thermocouple, a draft affecting the pilot flame, or a dirty pilot orifice. The thermocouple is the most common cause on tanks over 5 years old.
Here's what each cause looks like and how to tell them apart.
Why Does the Pilot Light on My Water Heater Keep Going Out?
The thermocouple is a small copper sensor that sits in the pilot flame. Its job is to prove to the gas valve that the pilot is lit, so it's safe to keep the gas supply open. When the thermocouple wears out or gets coated in soot, it stops sending that signal properly, and the gas valve shuts off the pilot as a safety measure, even though the flame was actually burning fine.
If your pilot lights, stays on for a few seconds to a couple of minutes after you release the pilot button, then goes out, a worn thermocouple is the most likely cause. This is a low-cost, quick repair.
A Draft Near the Water Heater
Water heaters are often installed in basements, closets, or crawl spaces, and a draft from a nearby vent, door, or gap in the space can blow out the pilot flame directly. This is more common in older Vancouver homes where the water heater sits in an unfinished basement area with less-sealed ductwork or venting nearby.
If the pilot goes out inconsistently, sometimes staying lit for days and other times going out within hours, and especially if it correlates with windy weather or the furnace running nearby, a draft is worth ruling out before assuming it's the thermocouple.
A Dirty or Clogged Pilot Orifice
The pilot orifice is the tiny opening that the gas flows through to create the pilot flame. Dust, soot, or debris can partially clog it over time, causing a weak or flickering flame that doesn't reliably contact the thermocouple. A weak, small, or yellow flame (instead of a strong blue one) is the tell here.
How to Relight the Pilot Safely
Most gas water heaters have the same basic relighting steps, usually printed on a label on the front of the unit:
- Turn the gas control knob to "off" and wait 5 minutes for any gas to clear.
- Turn the knob to "pilot."
- Press and hold the pilot button while lighting the pilot with a long lighter or match, following your specific model's instructions.
- Hold the button for about 30 to 60 seconds after the flame catches, to let the thermocouple heat up enough to hold the gas valve open on its own.
- Release the button and turn the knob to "on."
If the pilot won't stay lit after two or three honest attempts following these steps, stop trying to force it. Repeated attempts to relight a pilot that won't hold usually mean a part needs replacing, not more patience.
When to Call a Professional
If you smell gas at any point, whether or not the pilot is lit, stop immediately, don't attempt to light anything, and call your gas utility or a licensed plumber right away. That's not a DIY troubleshooting situation under any circumstances.
For a pilot that simply won't stay lit despite proper relighting attempts, a thermocouple replacement is a quick, inexpensive fix for a licensed plumber, and not something worth guessing at with repeated relighting attempts. Our team handles this kind of water heater repair across Vancouver, usually resolved in a single visit.
Frequently Asked Questions
Can I replace a thermocouple myself?
It's a fairly simple part to replace and some homeowners do it themselves, but it does involve working with the gas control valve. If you're not comfortable with that, it's a quick, low-cost job for a licensed plumber.
Is a pilot light that keeps going out dangerous?
The pilot going out on its own isn't dangerous, since the safety mechanism (the thermocouple) is doing exactly what it's designed to do by shutting off gas flow when it doesn't detect a flame. It becomes a concern only if you smell gas, which means stopping immediately and calling a professional rather than continuing to relight it.
A pilot that won't hold is one of the more straightforward water heater problems out there, and usually a fast fix once diagnosed. If yours keeps going out after trying the steps above, call Pioneer Plumbing & Heating at (604) 872-4946 for water heater repair done right the first time.
