American Dryer Corp. MD-170 - Manual (Page 31)

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3. Piping/Connections
ALL components/materials must conform to National Fuel 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.
The dryer is provided with a 1-1/2-inch N.P.T. inlet pipe connection extending out the back area of the burner
box. The minimum pipe size connection (supply line) to the dryer is 1-1/2-inch N.P.T. For ease of servicing,
the gas supply line of each dryer must have its own shut-off valve.
The size of the main gas supply line (header) will vary depending on the distance this line travels from the gas
meter or, in the case of L.P. (liquid propane) gas, the supply tank, other gas-operated appliances on the same
supply line, etc. Specific information regarding supply line size should be determined by the gas supplier.
NOTE: Undersized gas supply piping can create a low or inconsistent pressure which will result in
erratic operation of the burner ignition system.
Consistent gas pressure is essential at ALL gas connections. It is recommended that a 1-inch (2.54 cm) 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
(29.9 mb) pressure.
IMPORTANT: A water column pressure of 3.5 inches (8.7 mb) for natural gas and 10.5 inches
(26.1 mb) for L.P. dryers is required at the gas valve pressure tap of each dryer for
proper and safe operation.
A 1/8-inch 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 and L.P. gases must be used.
IMPORTANT: Test ALL connections for leaks by brushing on a soapy water solution (liquid
detergent works well).
WARNING: NEVER TEST FOR GAS LEAKS WITH A FLAME!!!
ALL components/materials must conform to National Fuel Gas Code Specifications ANSI Z223.1-
LATEST EDITION.
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.