American Dryer Corp. ML-170 - Manual (Page 22)

22 American Dryer Corp. 113360 - 8
3. Piping/Connections
ALL components/materials must conform to National Fuel Gas Code Specifications ANSI Z223.1-LATEST
EDITION, or in Canada, CAN/CGA-B149.1-M91 (Natural Gas) or CAN/CGA-B149.2-M91 (Liquid Propane
[L.P.] Gas) or LATEST EDITION (for General Installation and Gas Plumbing), as well as local codes and ordinances
and must be done by a qualified professional. 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 being supplied.
The dryer is provided with a 1-1/2” N.P.T. inlet pipe connection extending out the back area of the burner box and
should not be reduced in size. For ease in servicing, the gas supply line of each dryer must have its own shutoff
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. gas, the supply tank, other gas operated appliances on the same 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 1-1/2” (3.81 cm) pipe gas
loop be installed in the supply line servicing 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 (29.9 mb) of water column (W.C.)
pressure.
NOTE: A consistent water column test 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” 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!!!
IMPORTANT: The dryer and its individual shutoff 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 shutoff
valve during any pressure test of the gas supply system at test pressures equal to or less than 1/2 psig
(3.5 kPa).