Modine Manufacturing MPR Installation And Service Manual page 11

Gas connections
Table 11.1 - Natural Gas Heating Gas Consumption
Furnace Size
Digit 6 Digit 18
(Btu/hr)
F 150,000
G 200,000
H 250,000
J 300,000
B
K 400,000
R 175,000
S 225,000
T 310,000
J 300,000
K 400,000
L 500,000
C 
L 600,000
U 350,000
V 450,000
K 400,000
L 500,000
M 600,000
Q 800,000
D 
1 900,000
2 1,000,000
3 1,200,000
4 1,400,000
5 1,600,000
Natural gas consumption based on a heating value of 1050 Btu/cu. ft.
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C-Cabinet units consist of two furnaces that together total the value shown in
k
Table 11.1.
D-Cabinet units consist of two furnaces that together total the value shown
l
in Table 11.1 for sizes up to 800,000 Btu/hr. For sizes over 800,000 Btu/hr,
the unit consists of four furnaces that together total the value shown in Table
11.1.
Table 11.2 - Gas Pipe Capacities (Cu. Ft. per Hour) m
Pipe
length
1"
(feet)
10 520
20 350
30 285
40 245
50 215
60 195
70 180
80 170
90 160
100 150
125 130
150 120
Gas pipe capacities based on gas pressure up to 14" W.C. through Schedule
m
40 pipe with a pressure drop of 0.3" W.C. for Natural gas with a specific
gravity of 0.60.
Gas Consumption Gas
(CFH)  Connection
143 1/2"
190 3/4"
238 3/4"
286 3/4"
381 3/4"
167 1/2"
214 3/4"
295 3/4"
286 3/4"
381 1"
476 1"
571 1"
333 1"
429 1"
381 1.5" x 2
476 1.5" x 2
571 1.5" x 2
762 1.5" x 2
857 1.5" x 2
952 1.5" x 2
1143 1.5" x 2
1333 1.5" x 2
1524 1.5" x 2
Gas Pipe diameter
1-1/4" 1-1/2"
1050 1600
730 1100
590 890
500 760
440 670
400 610
370 560
350 530
320 490
305 460
275 410
250 380
3. The gas piping to the unit can enter the unit from the side
of the unit (refer to the unit dimensions) or from below (refer
to the base dimensions). A drill locator sticker and dimple is
located on the side of the unit to indicate the safe area for
drilling the hole for side gas pipe entry on B- and C-Cabinet
sized units. D-Cabinet sized units include a holes with
grommets for side pipe entry. 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
11.1). Verify the manual shut-off valve is gas tight on an
annual basis.
note: For bottom piped units, 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 the side, followed by
the manual shut-off valve, piped back into the unit side, 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 Figure 11.1).
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 11.1 - Recommended Sediment Trap/Manual
shut-off valve installation
2"
3050
2100
1650
1450
1270
1150
1050
990
930
870
780
710
GAS
SUPPLY LINE
Valve is in the "OFF" position when handle is perpendicular to pipe.
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MCP15-500.7
GAS
SUPPLY LINE
MANUAL GAS 
SHUT-OFF VALVE
GAS
SUPPLY LINE
PLUGGED
3" 1/8" NPT TEST
MIN. GAUGE CONNECTION
SEDIMENT
TRAP
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MANUAL GAS
SHUT-OFF VALVE
3"
MIN.
SEDIMENT
TRAP
GROUND JOINT
UNION WITH
BRASS SEAT
TO GAS
CONTROLS
TO
CONTROLS
PLUGGED 1/8"
NPT TEST GAUGE
CONNECTION
Through hole
in bottom of unit.
(caulk hole to prevent
water leakage.)
GROUND
JOINT
UNION
W/ BRASS
SEAT
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