Gas Connections - Modine Manufacturing IFS 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 minimumm rated input of dual rated units.
CAUTION
Purging of air from gas supply line 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 11.2. 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 10.1
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. 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 10.1).
4. Provide a sediment trap before each unit in the line where
low spots cannot be avoided. (See Figure 10.1).
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.
10
Figure 10.1 - Recommended Sediment Trap/Manual Shut-
off Valve Installation - Side or Bottom Gas Connection
GAS
SUPPLY LINE
MIN.
j  M anual shut-off valve is in the "OFF" position when handle is perpendicular to pipe.
Table 10.1 - Burner Orifice Sizing and Gas Consumption
Model
Size
Cfh
75
Orifice Drill Size
Cfh
100
Orifice Drill Size
Cfh
125
Orifice Drill Size
Cfh
150
Orifice Drill Size
Cfh
175
Orifice Drill Size
Cfh
200
Orifice Drill Size
Cfh
225
Orifice Drill Size
Cfh
250
Orifice Drill Size
Cfh
300
Orifice Drill Size
Cfh
350
Orifice Drill Size
Cfh
400
Orifice Drill Size
j Based on natural gas properties of 1040 Btu/Cu. Ft. and specific gravity of 0.60.
k  B ased on propane gas properties of 2500 Btu/Cu. Ft. and specific gravity of 1.53.
Table 10.2 - Gas Pipe Capacities (Cu. Ft. per Hour) j
Pipe
Length
(feet) 1/2"
10 132
20 92
30 73
40 63
50 56
60 50
70 46
80 43
90 40
100 38
125 34
150 31
j Capacities in Cubic Feet per Hour through Schedule 40 pipe with maximum
0.3" W.C. pressure drop with up to 14" W.C. gas pressure. Specific gravity is 0.60
for Natural gas and 1.50 for Propane gas.
k For Pipe Capacity with Propane Gas, divide Natural gas capacity by 1.6. Example:
What is the Propane gas pipe capacity for 60 feet of 1-1/4" pipe? The Natural gas
capacity is 400 CFH. Divide by 1.6 to get 250 CFH for Propane gas.
AIR 5-593.9
GAS
GROUND
SUPPLY LINE
JOINT
UNION
W/ BRASS
SEAT
MANUAL GAS
SHUT-OFF VALVE
CONTROLS
PLUGGED
3" 1/8" NPT TEST
GAGE CONNECTION
SEDIMENT
TRAP
Gas Type
Natural j Propane k
72.1 30.0
20 39
96.1 40.0
30 45
120.2 50.0
25 42
144.2 60.0
30 45
168.3 70.0
27 43
192.3 80.0
23 42
216.3 90.0
20 39
240.4 100.0
25 42
288.7 120.0
20 39
336.5 140.0
27 43
384.6 160.0
23 42
Natural Gas k
3/4" 1" 1-1/4"
278 520 1050
190 350 730
152 285 590
130 245 500
115 215 440
105 195 400
96 180 370
90 170 350
84 160 320
79 150 305
72 130 275
64 120 250
TO
Orifice Qty
1
2
2
3
3
3
3
4
4
6
6
1-1/2" 2"
1600 3050
1100 2100
890 1650
760 1450
670 1270
610 1150
560 1050
530 990
490 930
460 870
410 780
380 710