A bypass refers to a small gas flow path that allows a minimal amount of gas to pass at stove’s minimum flame — typically used for simmering.

What is a Bypass in a Gas Stove Safety Valve?

It is a tiny hole or channel inside the gas valve or burner. It allows a very small, controlled gas flow for the lowest flame setting, like when you turn the knob to "low" or "simmer."

The bypass works independently of the main valve opening — it ensures the flame stays on even when the valve is nearly shut.

Example:
When you cook on a low flame (just a small blue flame), the bypass hole is supplying the gas.
If it’s not set properly, the flame may go out on low, or be too strong for simmering.

In below picture, the bypass hole is inside the valve hollow shaft.

Bypass Adjustment
Some gas valves have a bypass screw (or adjustment screw) that allows technicians to fine-tune the minimum flame.

Especially important when converting between natural gas (NG) and liquefied petroleum gas (LPG), because the required bypass size differs due to different gas pressure and energy content.

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