Water Heater Pilot Light Troubleshooting — Complete Guide
Published: July 23, 2026 — CANRO Heating & Cooling — Greater Vancouver, BC
Pilot Will Not Light
Check that the gas supply valve is fully open. Ensure the gas control knob is set to PILOT. Press and hold the reset button while sparking or lighting. Wait 5 minutes before retrying if gas has accumulated. If the pilot will not light after 3 attempts, the pilot orifice may be clogged (clean with a small wire) or the gas control valve may have failed.
Pilot Lights But Will Not Stay Lit
The thermocouple is the most likely cause — it is not generating enough voltage to keep the gas valve open. Replace the thermocouple ($20-50 part). Other causes: the pilot flame is not touching the thermocouple tip (adjust the thermocouple position), the pilot orifice is partially blocked (clean it), or a draft is blowing out the pilot (check for nearby vents or open windows).
Pilot Flame Is Weak or Yellow
A weak pilot flame indicates a partially blocked orifice — clean it with compressed air or a small wire. A yellow flame indicates incomplete combustion — check for adequate combustion air. The flame should be mostly blue with a small yellow tip at the end. If the flame is mostly yellow, call a licensed gas fitter to inspect.