A pilot light that will not stay lit can be caused by drafts, a failed thermocouple or sensor, a dirty pilot, gas control problems, or combustion issues. Do not adjust gas valves or defeat safety devices. If you smell or hear leaking gas, leave the home without operating lights or phones and contact the gas utility or emergency services from outside.
If you smell gas, do not try relighting
Stop any relighting attempt and leave. Do not search for a leak with a flame or create sparks by operating switches. The priority is having the supply and appliance evaluated before returning or relighting.
Use only the manufacturer’s lighting procedure
Some water heaters use electronic ignition while others have an accessible pilot control. Read the appliance label and follow waiting times. If the control will not hold the flame after the normal procedure, do not hold or block it in position.
A flame that dies when the control is released points to the safety circuit
A thermocouple or flame sensor confirms flame before continuous gas is allowed. Dirt, mispositioning, or failure can prevent that confirmation, but diagnosing or replacing gas components should follow manufacturer procedures and local requirements.
Repeated outages call for service
Venting, draft, gas control, or combustion may be involved. A water heater with soot, abnormal yellow flame, burning odor, or repeated pilot failure should remain out of service until checked by qualified personnel.
Sources
- U.S. Consumer Product Safety Commission — Winter Weather Safety Tips — If gas is smelled or heard leaking, leave without operating electronics and contact gas authorities from outside.