Reznor XE Unit Installation Manual - Manual (Page 16)

Form I-XE/CRGB/RPB, P/N 131782 Rev 5, Page 15
Sizing Gas
Supply Lines
Pipe joint compounds (pipe dope) shall be resistant to the ac-
tion of liquefied petroleum gas or any other chemical con-
stituents of the gas being supplied.
Install a ground joint union and manual shutoff valve upstream of
the unit control system, as shown in FIGURES 16 and 17. The
1/8" plugged tapping in the shutoff valve provides connection for
supply line pressure test gauge. The National Fuel Gas Code re-
FIGURE 16 - Gas Connection Location, Indoor Model
Thermostat Wire Manual Shutoff Valve
with 1/8” NPT plugged
tapping must be installed
above unit casing.
Line Voltage
(Supply)
Junction
Box
To Gas Controls
and Burner
Ground
Joint
Union
Top View
Side View
4” (102mm)
2-3/32” (53mm)
5-5/8” (143mm)
6-7/8” (175mm)
7/8” (22mm) dia. 1-7/8” x 1-3/8” (48x35mm)
Minimum 1” (25mm) clearance between
heater access panel and elbow or fitting
Install a 1/8” NPT plug with tap
for test gauge immediately upstream
of the gas supply connection
Manual shutoff valve
Installer supplies
manual shutoff,
ground unions
and shaded piping
Gas Supply
Entrance
5
-3/4”
(146mm)
Condensate
Weep Holes
FIGURE 17 - Gas Connection Location, Outdoor Models
Install the gas supply piping
so that when the union is
disconnected, the supply pipe
will not interfere with the
removal of the burner rack.
(The burner rack slides out
of the control side of the
furnace.)
Sizes Natural Propane Sizes Natural Propane
75-250 1/2" 1/2" 300-400 3/4" 1/2"
Gas Connection to S ingle-S tage Valve (Not Gas Supply Line Size)
Applies to all M odels in this M anual
quires the installation of a trap with a minimum 3" (76mm) drip leg. Local
codes may require a minimum drip leg longer than 3" (76mm), typically 6"
(152mm).
After all connections are made, disconnect the pilot supply at the control
valve and bleed the system of air. Reconnect the pilot line and leak-test all
connections by brushing on a soap solution.
WARNING: All components of a gas supply system
must be leak tested prior to placing equipment in
service. NEVER TEST FOR LEAKS WITH AN
OPEN FLAME. Failure to comply could result in
personal injury, property damage or death.
Capacity of Piping
Cubic Feet per Hour based on 0.3" w.c. Pressure Drop
Specific Gravity for Natural Gas -- 0.6 (Natural Gas -- 1000 BTU/Cubic Ft)
Specific Gravity for Propane Gas -- 1.6 (Propane Gas -- 2550 BTU/Cubic Ft)
Length Diameter of Pipe
of 1/2" 3/4" 1" 1-1/4" 1-1/2" 2"
Pipe Natural Propane Natural Propane Natural Propane Natural Propane Natural Propane Natural Propane
20' 92 56 190 116 350 214 730 445 1100 671 2100 1281
30' 73 45 152 93 285 174 590 360 890 543 1650 1007
40' 63 38 130 79 245 149 500 305 760 464 1450 885
50' 56 34 115 70 215 131 440 268 670 409 1270 775
60' 50 31 105 64 195 119 400 244 610 372 1105 674
70' 46 28 96 59 180 110 370 226 560 342 1050 641
80' 43 26 90 55 170 104 350 214 530 323 990 604
90' 40 24 84 51 160 98 320 195 490 299 930 567
100' 38 23 79 48 150 92 305 186 460 281 870 531
125' 34 21 72 44 130 79 275 168 410 250 780 476
150' 31 19 64 39 120 73 250 153 380 232 710 433
175' 28 17 59 36 110 67 225 137 350 214 650 397
200' 26 16 55 34 100 61 210 128 320 195 610 372
Note: When sizing supply lines, consider possibilities of future expansion and increased requirements.
Refer to National Fuel Gas Code for additional information on line sizing.
Manifold or Orifice Pressure Settings
Measuring gas valve outlet (manifold) pressure cannot be done until
the heater is in operation. It is included in the "Check-Test-Start"
section, Paragraph 30. The following instructions apply.
WARNING: Manifold gas pressure must never
exceed 3.5" w.c. for natural gas and 10" w.c. for
propane gas.
For Natural Gas: When the heater leaves the factory, the combination
valve is set so that the outlet gas pressure of a single-stage valve or high fire
of a two-stage valve is regulated to 3.5" w.c. Low fire on a two-stage valve
is set to 1.8" w.c. Inlet supply pressure to the valve must be a minimum of
5" w.c. or as noted on the rating plate and a maximum of 14" w.c. NOTE:
Always check the rating plate for minimum gas supply pressure. Mini-
mum supply pressure requirements vary based on size of burner and the
gas control option. Most units require a minimum of 5" w.c. of natural gas