American Dryer Corp. Gas/Electric/Steam AD-75HS - Manual (Page 33)

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Consistent gas pressure is essential at ALL gas connections. It is recommended that a 3/4-inch pipe gas loop
be installed in the supply line serving a bank of dryers. An in-line pressure regulator must be installed in the
gas supply line (header) if the (natural) gas pressure exceeds 12.0 inches of water column (W.C.) pressure.
NOTE: A water column (W.C.) test pressure of 3.5 - 4.0-inches for natural gas and 11.0-inches for
L.P. (liquid propane) dryers is required at the gas valve pressure tap of each dryer for proper
and safe operation.
A 1/8" N.P.T. plugged tap, accessible for a test gauge connection, must be installed in the main gas supply
line immediately upstream of each dryer.
IMPORTANT: Pipe joint compounds that resist the action of natural gas and L.P. gas must be used.
IMPORTANT: Test ALL connections for leaks by brushing on a soapy water solution (liquid
detergent works well).
WARNING: NEVER TEST FOR LEAKS WITH A FLAME!!!
ALL components/materials must conform to National Gas Code specifications. It is important that gas
pressure regulators meet applicable pressure requirements and that gas meters be rated for the total amount
of ALL the appliance BTU's being supplied.
IMPORTANT: The dryer and its individual shut-off valve must be disconnected from the gas supply
piping system during any pressure testing of that system at test pressures in excess of
1/2 psig (3.5 kPa).
NOTE: The dryer must be isolated from the gas supply piping system by closing its individual manual
shut-off valve during any pressure test of the gas supply system at test pressures equal to or
less than 1/2 psig (3.5 kPa).