A gas burner that won’t stay lit can turn your cooking routine into a frustrating experience. You ignite the flame, hold the knob down, but as soon as you release it—poof, the flame goes out. This common issue is more than just inconvenient; it’s also a safety concern. Two of the most frequent causes behind this problem are a faulty thermocouple and weak gas pressure. Understanding how these systems work will help you know when it’s time to call for professional repair.
How the Thermocouple Works
The thermocouple is a small, heat-sensitive safety device located near the burner flame. Its primary function is to detect whether the flame is burning. When you light the burner and the flame heats the thermocouple, it generates a small electrical current. This current signals the gas valve to stay open, allowing gas to continue flowing. If the thermocouple is faulty, misaligned, or dirty, it may fail to detect the flame properly. As a result, once you release the knob, the gas valve automatically shuts off to prevent unburned gas from leaking—a critical safety mechanism but a frustrating one when it happens repeatedly.Signs of a Faulty Thermocouple
- Burner lights but goes out immediately when you release the knob.
- The pilot light doesn’t stay lit or flickers frequently.
- The flame appears weak or inconsistent.
- Other burners work fine, isolating the issue to a single one.
Weak Gas Pressure as a Cause
Another possible reason your gas burner keeps going out is weak gas pressure. Gas needs to flow at a consistent rate to maintain a stable flame. If the pressure is too low, the burner won’t get enough gas to sustain ignition after you release the knob. Low gas pressure can be caused by several factors:- Partially closed gas supply valve
- Clogged gas line or regulator
- Faulty pressure regulator on the appliance
- Issues with the household gas supply line
Safety First
If you suspect a gas pressure issue, avoid repeatedly trying to ignite the burner. Gas leaks can occur if the valve is opened too long without ignition. You should immediately:- Turn off all burner knobs.
- Open windows for ventilation.
- Avoid using electrical switches or open flames.
- Call a professional technician to inspect the appliance safely.
How a Technician Diagnoses the Problem
Professional appliance repair technicians use specialized tools to test the thermocouple and gas pressure.- Thermocouple Testing: The technician measures the millivolt output of the thermocouple when heated. If it’s below the required voltage, it will need cleaning, adjustment, or replacement.
- Gas Pressure Check: The technician connects a manometer to check the incoming gas pressure and ensure it matches the manufacturer’s specifications.
- Burner Inspection: The flame pattern, color, and strength are examined. A blue, steady flame indicates proper gas-to-air ratio, while a yellow or flickering flame suggests poor combustion or low gas pressure.
Preventing Future Problems
To avoid having your gas burner go out again, regular maintenance is key.- Clean the burners regularly to remove grease, food particles, or oxidation that may affect gas flow.
- Keep the thermocouple clean and ensure it’s properly aligned with the flame.
- Have your gas connections inspected annually by a qualified technician. This ensures that all components work safely and efficiently.
- Use only authorized replacement parts if any component is faulty. Low-quality parts may not perform reliably or safely.