Abstract: A bypass valve is connected in line with the distribution line of a gas meter and includes a cylindrical housing with an inlet port connected to the distribution line, an outlet port connected to the gas consumer, and a poppet cage defined by two annular seats disposed internally between the two ports and formed with flow apertures. The housing is formed with an auxiliary port disposed between the inlet port and the outlet port. A threaded fitting for connecting to an auxiliary gas source extends through the auxiliary port and connects to the outlet seat of the cage. A cylindrical poppet is slidably disposed within the cage and is biased against the outlet seat by a coil spring interposed between the poppet and the inlet seat.