Questar Gas - Good Practices for Gas Piping and Appliance ...

MAKE-UP AIR - Air being provided to replace air being exhausted.
MANIFOLD - The conduit of an appliance which supplies gas to
the individual burners.
MANOMETER - Instrument for measuring gas pressure.
MANUAL MAIN SHUT-OFF VALVE - A manually operated valve
in the gas line for the purpose of completely turning on or shutting
off the gas supply to the appliance, except to pilot or pilots which
are provided with independent shut-off valves.
MECHANICAL DRAFT SYSTEM - A device installed in and
made a part of the vent which will provide a positive induced draft.
METER - An instrument installed to measure the volume of gas
being delivered.
MICROAMPERE - One millionth of an ampere.
MILLIAMPERE - One thousandth of an ampere.
MILLIVOLT - One thousandth of a volt.
MIXER - The combination of mixer head, mixer throat and mixer
tube.
a. Mixer Head: That portion of an injection (Bunsen) type burner,
usually enlarged, which primary air flows to mix with the gas
stream.
b. Mixer Throat: That portion of the mixer which has the smallest
cross-sectional area and lies between the mixer head and the
mixer tube.
c. Mixer Tube: That portion of the mixer which lies between the
throat and the burner head.
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