Lennox International Inc 15GCSX Compressors, Gas Supply and Piping, Gas Heat Application Data

Compressors

Units are shipped with the compressor mountings factory−adjusted and ready for operation.

CAUTION

Do not loosen compressor mounting bolts.

Gas Supply and Piping

Check the unit rating plate to confirm whether unit is equipped for use with natural gas or LP/propane. If conversion is required use the approved conversion kit.

NOTE − Units are shipped equipped for natural gas, but can be converted to LP/propane with a conversion kit. Conversion must be performed by an approved licensed pipe fitter or technician.

All LP/propane gas equipment must conform to the safety standards of the National Fire Protection Association. Complete information regarding tank sizing for vaporization, recommended regulator settings, and pipe sizing is available from most regulator manufacturers and LP/propane gas suppliers.

Proper sizing of gas piping depends on the cubic feet per hour of gas flow required, specific gravity of the gas and length of run. In the United States, the current National Fuel Gas Code Z223.1 should be followed in all cases unless superseded by local codes or gas company requirements. Refer to tables 2 and 3. In Canada, refer to the current CSA B.149 installation codes.

Table 2

Gas Heat Application Data

Unit	Input Rating	Output Rating	Gas Capacity*
Heating Size	(Btu)	(Btu)	(FT3 / HR)
68	67,500	54,000	63
83	82,500	66,000	77
90	90,000	72,000	84
110	110,000	88,000	102
138	137,500	110,000	128

*Based on 1075 Btu per cubic foot of natural gas.

Before connecting piping, check with gas company or authorities having jurisdiction for local codes or requirements. When installing gas supply piping, length of run from gas meter must be considered in determining pipe size for 0.5 inch w.c. maximum pressure drop. Do not use supply pipe smaller than unit

gas connection. For natural gas unit, supply pressure at the unit gas connection must be a minimum of 5 inches w.c. and a maximum of 10.5 w.c. For LP/propane gas units, supply pressure at the unit gas connection must be a minimum of 11 inches w.c. and a maximum of 13.0 inches w.c.

Table 3

Gas Pipe Capacity−FT3 / HR

	Nominal Iron Pipe Size (inches)
Length in Feet
	1/2 in.	3/4 in.	1 in.	1−1/4 in.
10	132	278	520	1050
20	92	190	350	730
30	73	152	285	590
40	63	130	245	500
50	56	115	215	440
60	50	105	195	400
70	46	96	180	370
80	43	90	170	350
90	40	84	160	320
100	38	79	150	305

The gas supply piping should be routed through the grommet on the side of the unit. Refer to figure 7.

Gas Piping and Electrical Conduit Access

Gas Line Entry

Thermostat

Entry

Line Voltage

Entry

Figure 7

When making piping connections, a drip leg should be installed on vertical runs to serve as a trap for sediment or condensate. A 1/8 inch N.P.T. tap accessible for test gauge connection must be provided in field piping upstream from gas supply connection to unit. Install a ground joint union between gas control manifold and the manual main shut−off valve. See figure 8.

Compounds used on threaded joints of gas piping shall be resistant to the action of propane/LP gases.

Page 10