Modine Manufacturing HFG Series, Installation And Service Manual

Page: 6 / 24

5-571.4
66
installation
gas connections (continued)
1. Installation of piping must conform with local building codes,
or in the absence of local codes, with the National Fuel Gas
Code, ANSI Z223.1 (NFPA 54) - Latest Edition. In Canada,
installation must be in accordance with CAN/CGA-B149.1 for
natural gas units and CAN/CGA-B149.2 for propane units.
2. Piping to units should conform with local and national
requirements for type and volume of gas handled, and
pressure drop allowed in the line. Refer to Table 9.1 to
determine the cubic feet per hour (cfh) for the type of gas
and size of unit to be installed. Using this cfh value and the
length of pipe necessary, determine the pipe diameter from
Table 6.1. Where several units are served by the same
main, the total capacity, cfh and length of main must be
considered. Avoid pipe sizes smaller than 1/2". Table 6.1
allows for a 0.3" W.C. pressure drop in the supply pressure
from the building main to the unit. The inlet pressure to the
unit must be 6-7" W.C. for natural gas and 11-14" W.C. for
propane gas. When sizing the inlet gas pipe diameter, make
sure that the unit supply pressure can be met after the 0.3"
W.C. has been subtracted. If the 0.3" W.C. pressure drop is
too high, refer to the Gas Engineer’s Handbook for other gas
pipe capacities.
3. The gas piping to the unit can enter the unit from the side
of the unit or from below (curb mounted units). Drill locator
dimples are located in the side and bottom of the unit for
field drilling the hole for the gas pipe entry.
for side piped units
Install a ground joint union with brass seat and a manual
shut-off valve external of the unit casing, and adjacent to the
unit for emergency shut-off and easy servicing of controls,
including a 1/8" NPT plugged tapping accessible for test
gauge connection (See Figure 6.1).
for bottom piped units
Install a ground joint union with brass seat and a manual
shut-off valve internal to the unit casing for easy servicing of
controls, including a 1/8" NPT plugged tapping accessible for
test gauge connection (See Figure 6.2).
note: Some local
codes may require a manual shutoff valve external to the unit
casing. In this case, the gas piping must exit the unit through
a side piping hole, followed by the manual shut-off valve,
piped back into the unit corner post, through the unit bottom,
and lead to an additional union and manual shut-off valve.
4. Provide a sediment trap before each unit in the line where
low spots cannot be avoided. (See Figures 6.1 & 6.2).
5. When Pressure/Leak testing, pressures above 14" W.C.
(1/2 psi), close the field installed shut-off valve, disconnect
the appliance and its combination gas control from the gas
supply line, and plug the supply line before testing. When
testing pressures 14" W.C. (1/2 psi) or below, close the
manual shut-off valve on the appliance before testing.
figure 6.1
recommended sediment trap/manual shut-off valve
installation - side gas connection
figure 6.2
recommended sediment trap/manual shut-off valve
installation - bottom gas connection
➀
Manual shut-off valve is in the “OFF” position when handle is perpendicular to
pipe.
table 6.1 -
gas Pipe capacities
gas Pipe capacities (up to 14” W.c. gas Pressure through schedule 40 Pipe)
cubic feet per Hour with Pressure Drop of 0.3” W.c.
natural gas - specific gravity - 0.60
Propane gas - specific gravity - 1.50
length Pipe Diameter
of Pipe 1/2" 3/4" 1" 1-1/4" 1-1/2" 2"
(feet) natural Propane natural Propane natural Propane natural Propane natural Propane natural Propane
10 132 83 278 175 520 328 1050 662 1600 1008 3050 1922
20 92 58 190 120 350 221 730 460 1100 693 2100 1323
30 73 46 152 96 285 180 590 372 890 561 1650 1040
40 63 40 130 82 245 154 500 315 760 479 1450 914
50 56 35 115 72 215 135 440 277 670 422 1270 800
60 50 32 105 66 195 123 400 252 610 384 1150 725
70 46 29 96 60 180 113 370 233 560 353 1050 662
80 43 27 90 57 170 107 350 221 530 334 990 624
90 40 25 84 53 160 101 320 202 490 309 930 586
100 38 24 79 50 150 95 305 192 460 290 870 548
125 34 21 72 45 130 82 275 173 410 258 780 491
150 31 20 64 40 120 76 250 158 380 239 710 447
GAS
SUPPLY LINE
GAS
SUPPLY LINE
GROUND
JOINT
UNION
W/ BRASS
SEAT
MANUAL GAS
SHUT-OFF VALVE
3"
MIN.
SEDIMENT
TRAP
PLUGGED
1/8" NPT TEST
GAGE CONNECTION
TO
CONTROLS
➀
GAS
SUPPLY LINE
GROUND
JOINT
UNION
W/ BRASS
SEAT
MANUAL GAS
SHUT-OFF VALVE
3"
MIN.
SEDIMENT
TRAP
TO
CONTROLS
PLUGGED 1/8"
NPT TEST GAGE
CONNECTION
Through hole
in bottom of unit.
(caulk hole to prevent
water leakage.)
➀