Reznor RXH (Outdoor PreevA) Unit Installation Manual - Manual (Page 16)

Form I-RDH/REH/RHH/RXH (12-14), Page 16
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 of
Pipe
Diameter of Pipe
1/2” 3/4” 1” 1-1/4” 1-1/2” 2”
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.
TABLE 10B - Sizing Gas
Supply Lines
Inlet Pressure (applies to all gas controls)
Before attempting to measure or adjust valve outlet gas pressure, the inlet (supply)
pressure must be within the specified range both when the heater is in operation and
on standby. Incorrect inlet (supply) pressure could cause excessive outlet gas pres-
sure immediately or at some future time. If natural gas inlet (supply) pressure is too
high, install a regulator in the supply line before it reaches the heater. If natural gas
supply pressure is too low, contact your gas supplier.
Inlet pressure to the valve for natural gas must be a minimum of 5” w.c. or as noted
on the rating plate and a maximum of 14” w.c. Inlet supply pressure to the valve for
propane gas must be a minimum of 11” w.c. and a maximum of 14” w.c.
Manifold Pressure at the Burner Orifice
Measuring manifold gas pressure cannot be done until the heater is in operation. It is
included in the “Check After Startup” steps, Paragraph 9.3. The procedure required
depends on the type of gas control option:
• Single and Two Stage Options
AG1, AG2, AG3, AG15, AG16, AG60, AG61,
AG62, DG1, DG5, D12C - Follow INSTRUCTIONS starting below;.
• Electronic Modulation (2:1 turndown) Options.AG8, AG9, AG9H - Follow
instructions on pages 17-18.
• Electronic Modulation (4:1 turndown) Options.AG40, DG2, DG6, D12B -
Follow instructions on pages 17-18.
• Electronic Modulation (8:1 turndown) Options AG58, D12G - Follow
instructions on pages 18-19.
All gas pressure measurements should be done with a manometer (fluid-filled gauge)
rather than a spring type gauge due to the difficulty of maintaining calibration. Use a
water column manometer readable to the nearest tenth of an inch.
6.1.2 Checking Burner
Gas Pressure
NOTE: If unsure of the
Gas Control Option Code
(AG1, AG2, AG3, AG8,
AG9, AG9H, AG15, AG16,
AG40, AG58, AG60, AG61,
AG62, DG1, DG2, DG5,
DG6, D12B, D12C, or
D12G), check the wiring
diagram on the heater. All
option codes affected by
electrical power are listed
on the bottom of the wir-
ing diagram after the unit
Model and Size.
6.0 Mechanical
(cont’d)
6.1 Gas Piping and Pressures - Models RDH and RHH (cont’d)
TABLE 10A - Gas
Connection Sizes
From Gas Supply
(horizontal or vertical)
Manual
shutoff
Drip
Leg
*To Gas
Valve
(inside the
cabinet)
*To Gas
Valve
(inside the
cabinet) Ground
Joint
Union
Drip
Leg
Ground Joint Union
Manual shutoff
FIGURE 10 -
Gas
Connection
*See gas connection
location on dimension
drawing, page 7 or
page 9.
6.1.1 Gas Supply and Connections (cont’d)
RDH
75, 100,
125, 150,
175, 200
225, 250,
300, 350.
400A
RHH 130 & 180 260 & 350
Natural
Gas
1/2” 3/4”
Propane 1/2” 3/4”
NOTE: These are
not supply line sizes.