Gas Connections - Modine Manufacturing DFP Installation And Service Manual

INSTALLATION

Gas Connections

WARNING
1. All field gas piping must be pressure/leak tested prior to
operation. Never use an open flame. Use a soap solution or
equivalent for testing.
2. Gas pressure to appliance controls must never exceed 14"
W.C. (1/2 psi).
3. To reduce the opportunity for condensation, the minimum sea
level input to the appliance, as indicated on the serial plate,
must not be less than 5% below the rated input, or 5% below
the minimum rated input of duel rated units.
CAUTION
Purging of air from gas lines should be performed as
described in ANSI Z223.1 - latest edition "National Fuel Gas
Code", or in Canada in CAN/CGA-B149 codes.
IMPORTANT
To prevent premature heat exchanger failure, the input to the
appliance, as indicated on the serial plate, must not exceed
the rated input by more than 5%.
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 10.1 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 8.1. 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 8.1 allows for a 0.3"
Table 8.1 - Gas Pipe Capacities
Length
Of Pipe 1/2"
(feet) Natural Propane
10 132 83
20 92 58
30 73 46
40 63 40
50 56 35
60 50 32
70 46 29
80 43 27
90 40 25
100 38 24
125 34 21
150 31 20
8
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
3/4"
Natural Propane Natural
278 175 520
190 120 350
152 96 285
130 82 245
115 72 215
105 66 195
96 60 180
90 57 170
84 53 160
79 50 150
72 45 130
64 40 120
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. 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 8.1).
4. Provide a sediment trap before each unit in the line where low
spots cannot be avoided. (See Figure 8.1).
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 8.1 - Recommended Sediment Trap/Manual
Shut-off Valve Installation - Side or Bottom Gas
Connection
GAS
SUPPLY LINE
➀ Manual shut-off valve is in the "OFF" position when handle is perpendicular to
pipe.
Pipe Diameter
1" 1-1/4"
Propane Natural Propane
328 1050 662
221 730 460
180 590 372
154 500 315
135 440 277
123 400 252
113 370 233
107 350 221
101 320 202
95 305 192
82 275 173
76 250 158
5-564
GAS
GROUND
SUPPLY LINE
JOINT
UNION
➀ W/ BRASS
SEAT
MANUAL GAS
SHUT-OFF VALVE
CONTROLS
PLUGGED
3" 1/8" NPT TEST
MIN. GAGE CONNECTION
SEDIMENT
TRAP
1-1/2"
Natural Propane Natural
1600 1008 3050
1100 693 2100
890 561 1650
760 479 1450
670 422 1270
610 384 1150
560 353 1050
530 334 990
490 309 930
460 290 870
410 258 780
380 239 710
TO
2"
Propane
1922
1323
1040
914
800
725
662
624
586
548
491
447