American Dryer Corp ML-79 manual S. Drill Material Size equivalent are as follows

b. Gas Connections:
Inlet connection	3/4” inch N.P.T.
Inlet supply size	3/4” inch N. P.T.
Btu/hr input (per dryer)	200,000
1. Natural Gas

Regulation is controlled by the dryer’s gas valve’s internal regulator. Incoming supply pressure must be consistent between 6 and 12 inches water column pressure.

2. Liquid Propane (L.P.) Gas

Dryers made for use with L.P. gas have the gas valve’s internal pressure regulator blocked open so that the gas pressure must be regulated upstream of the dryer. The pressure measured at each gas valve pressure tap must be a consistent 11 inch water column. There is no regulator or regulation provided in an L.P. dryer. The water column pressure must be regulated at the source (L.P. tank) or an external regulator must be added to each dryer.

				Type of Gas					L.P.
			Natural			Liquid Propane			Conversion
									Kit Part
Model	BTU Per			Part				Part
									Number
	Hour	Qty.	D.M.S.*		Qty.		D.M.S.*
Number				Number				Number
	Rating
ML79 WW	200,000	4	#29	4	4		#47	140805	881231

*D.M.S. (Drill Material Size) equivalent are as follows:

Natural Gas	#29 = .1360”
Liquid Propane Gas	#47 = .0785”

3. Piping and Connections

ALL components and materials must conform to National Gas Code specifications. It is important that gas pressure regulators meet applicable pressure requirement and that gas meters be rated for the total amount of ALL the appliance BTU’s being supplied.

The dryer is provided with a 3/4” N.P.T. inlet pipe connection located at the right side of the base of the dryer. The minimum pipe size (supply line) to the dryer is 3/4” N.P.T. For ease 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 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.

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