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CAUTION
!
EQUIPMENT DAMAGE HAZARD
Failure to follow this caution may result in damage
to equipment.
When connecting the gas line to the unit gas valve,
the installer MUST use a backup wrench to prevent
damage to the valve.
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. Do not use a pipe smaller than the
size specified. 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:
horizontally 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. 15.
9" MINIMUM CLEARANCE
FOR PANEL REMOVAL
MANUAL GAS
SHUTOFF VALVE
BASE UNIT
48" MINIMUM
BASE RAIL
ROOF
CURB
FROM
LEGEND
GAS
NFGC – National Fuel Gas Code
METER
Field supplied.
*
NOTE: Follow all local codes.
STEEL PIPE
NOMINAL DIAMETER
(in.)
1
/
2
3
/
or 1
4
1
/
1
or larger
4
Fig. 15 − Gas Piping Guide
(with Accessory Thru−the−Curb Service Connections)
Factory−Option Thru−Base Connections
(Gas Connections) —
This service connection kit consists of a NPT gas adapter
fitting, an electrical bulkhead connector and a
electrical bulkhead connector, all factory−installed in the
embossed (raised) section of the unit basepan in the
condenser section. See Fig. 16.
X
GAS
REGULATOR
*
*
DRIP LEG
*
PER NFGC
FIELD-FABRICATED
*
SUPPORT
SPACING OF SUPPORTS
X DIMENSION
(ft)
6
8
10
C11091
3
/
−in
4
BRASS FITTING FOR 3 TO 6 TON UNITS.
Fig. 16 − Thru−Base Connection Fittings
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.
Check tightness of connector lock nuts before connecting
gas piping.
1
Gas Line: Install a
/
−in (08 & 09 size Low Gas units
2
3
only) or
/
−in (for all other units) NPT street elbow on
4
the thru−base gas fitting. Attach an appropriate size pipe
nipple with minimum length of 16−in (406 mm)
(field−supplied) to the street elbow and extend it through
the access panel at the gas support bracket. See Fig. 17.
BRASS FITTING
EMBOSSMENT
FOR 3-6 TON UNITS
Fig. 17 − Gas Line Piping
Other hardware required to complete the installation of
the gas supply line will include a manual shutoff valve, a
sediment trap (drip leg) and a ground−joint union. A
pressure regulator valve may also be required (to convert
gas pressure from pounds to inches of pressure). The
manual shutoff valve must be located within 6−ft (1.83 m)
of the unit. The union, located in the final leg entering the
unit, must be located at least 9−in (230 mm) away from
the access panel to permit the panel to be removed for
service. If a regulator valve is installed, it must be located
a minimum of 4−ft (1220 mm) away from the unit's flue
outlet. Some municipal codes require that the manual
shutoff valve be located upstream of the sediment trap.
See Fig. 18 and Fig. 19 for typical piping arrangements
for gas piping that has been routed through the sidewall of
the curb. See Fig. 20 for typical piping arrangement when
thru−base is used. Ensure that all piping does not block
access to the unit's main control box or limit the required
working space in front of the control box.
15
LOW VOLTAGE
CONDUIT
CONNECTOR
HIGH VOLTAGE
CONDUIT
CONNECTOR
C13410
SUPPORT
BRACKET
C13411
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