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16
Install a gas supply line that runs to the unit heating section. Refer
to the NFPA 54/NFGC or equivalent code for gas pipe sizing data.
Size the gas supply line to allow for a maximum pressure drop of
0.5 in. wg (124 Pa) between gas regulator source and unit gas
valve connection when unit is operating at high-fire flow rate.
The gas supply line can approach the unit in three ways: horizon
-
tally from outside the unit (across the roof), thru-curb/under unit
basepan (accessory kit required) or through unit basepan (factory-
option or accessory kit required). Consult accessory kit installation
instructions for details on these installation methods. Observe
clearance to gas line components per Fig. 19.
Fig. 19 —
Gas Piping Guide
FACTORY-OPTION THRU-BASE CONNECTIONS (GAS
CONNECTION)
This service connection kit consists of a
3
/
4
-in. NPT gas adapter
fitting (stainless steel), a
1
/
2
-in. electrical bulkhead connector and a
1
1
/
2
-in. electrical bulkhead connector, connected to an “L” bracket
covering the embossed (raised) section of the unit basepan in the
condenser section. See Fig. 20.
Fig. 20 —
Thru-the-Base Option, Shipping Position
1. Remove the “L” bracket assembly from the unit (see
Fig. 20).
2. Cut and discard the wire tie on the gas fitting. Hand
tighten the fitting if it has loosened in transit.
3. Remove connector plate assembly from the “L” bracket
and discard the “L” bracket, but retain the washer head
screws and the gasket (located between the “L” bracket
and the connector plate assembly.
NOTE: Take care not to damage the gasket, as it is reused in the
following step.
4. Place the gasket over the embossed area in the basepan,
aligning the holes in the gasket to the holes in the basepan.
See Fig. 21.
5. Install the connector plate assembly to the basepan using 8
of the washer head screws.
NOTE: If gas and/or electrical connections are not going to occur
at this time, tape or otherwise cover the fittings so that moisture
does not get into the building or conduit in the interim.
The thru-base gas connector has male and female threads. The
male threads protrude above the basepan of the unit; the female
threads protrude below the basepan.
Fig. 21 —
Completing Installation of Thru-the-Base
Option
Table 5 —
Natural Gas Manifold Pressure Ranges
UNIT MODEL
UNIT SIZE
HIGH FIRE
LOW FIRE
48LCD/E/S/R0
08, 09, 12
3.5 in. wg
(872 Pa)
2.0 in. wg
(498 Pa)
48LCF/T0
(High Heat
units only)
12 only
3.4 in. wg
(847 Pa)
2.3 in. wg
(573 Pa)
Table 6 —
Liquid Propane Manifold Pressure Ranges
UNIT MODEL
UNIT SIZE
HIGH FIRE
LOW FIRE
48LCD/E/S/R0
08, 09, 12
10.0 in. wg
(2491 Pa)
5.7 in. wg
(1420 Pa)
48LCF/T0
(High Heat
units only)
12 only
6.2 in. wg
(1554 Pa)
3.9 in. wg
(971 Pa)
CAUTION
EQUIPMENT DAMAGE
Failure to follow this caution may result in equipment damage.
When connecting the gas line to the unit gas valve, the installer
MUST use a backup wrench to prevent damage to the valve.
LEGEND
*
Field supplied.
NOTE:
Follow all local codes.
NFGC –
National Fuel Gas Code
STEEL PIPE
NOMINAL DIAMETER
(in.)
SPACING OF SUPPORTS
X DIMENSION
(ft)
1
/
2
3
/
4
or 1
1
1
/
4
or larger
6
8
10
X
BASE UNIT
BASE RAIL
ROOF
CURB
9” MINIMUM CLEARANCE
FOR PANEL REMOVAL
MANUAL GAS
SHUTOFF VALVE
*
GAS
REGULATOR
*
48” MINIMUM
DRIP LEG
PER NFGC
*
FIELD-
FABRICATED
SUPPORT
*
FROM
GAS
METER
1
1
/
2
” ELECTRICAL
BULKHEAD
CONNECTOR
1
/
2
” ELECTRICAL
BULKHEAD
CONNECTOR
3
/
4
” NPT GAS
ADAPTER
FITTING
GASKET
CONNECTOR
PLATE
ASSEMBLY
Summary of Contents for 48LC Series
Page 5: ...5 Fig 2 Unit Dimensional Drawing Size 08 Unit ...
Page 6: ...6 Fig 2 Unit Dimensional Drawing Size 08 Unit cont ...
Page 7: ...7 Fig 3 Unit Dimensional Drawing Size 09 and 12 Units ...
Page 8: ...8 Fig 3 Unit Dimensional Drawing Size 09 and 12 Units cont ...
Page 11: ...11 Fig 6 Roof Curb Details Size 08 12 Units ...
Page 21: ...21 Fig 34 48LC 08 12 Electro mechanical Control Wiring Diagram ...
Page 22: ...22 Fig 35 48LC 08 12 RTU Open Control Wiring Diagram ...
Page 23: ...23 Fig 36 48LC 08 12 SystemVu Control Wiring Diagram ...
Page 25: ...25 Fig 38 48LC 08 12 Typical Power Wiring Diagram SystemVu Control 208 230 v Unit Shown ...
Page 61: ......