"Mike Clarke" wrote in message
news
Heliotrope Smith wrote:

The white digits are hundreds of cubic feet and the red digits are tens
of
cubic feet so the moving red counter will revolve 10 times to increment
the white digit by 1.

The test dial records 1 cubic foot of gas per revolution and this is
used
to determine the gas rate of the appliance under test.

The text below the digits on the meter says that it's 0.071 ft^3 per
revolution which makes it 14.08 revolutions per ft^3 so that's about 140
revolutions for one red digit.

--
Mike Clarke

The 0.071 ft3/rev could be a bit misleading but it does not refer to the
test dial but to the internal volume of the measuring device.

This information is required to determine the amount of gas required to pass
when purging the gas installation.

The test dial does in fact show one cubic foot of gas passing for each
complete revolution.