Step 11 - Install Gas Piping; Factory-Option Thru-Base Connections (Gas Connections) - Carrier WeatherMaster 48HC04 Series Installation Instructions Manual

Step 11 — Install Gas Piping
Installation of the gas piping must be accordance with local
building codes and with applicable national codes. In U.S.A.,
refer to NFPA 54/ANSI Z223.1 National Fuel Gas Code (NF-
GC). In Canada, installation must be accordance with the
CAN/CSA B149.1 and CAN/CSA B149.2 installation codes
for gas burning appliances.
This unit is factory equipped for use with natural gas (NG) fuel
at elevations up to 2000 ft (610 m) above sea level. Unit may
be field converted for operation at elevations above 2000 ft
(610 m) and/or for use with liquefied petroleum fuel. See ac-
cessory kit installation instructions regarding these accessories.
NOTE: Furnace gas input rate on rating plate is for installation up
to 2000 ft (610 m) above sea level. In U.S.A., the input rating for
altitudes above 2000 ft (610 m) must be derated by 4% for each
1000 ft (305 m) above sea level. In Canada, the input rating must
be derated by 10% for altitudes of 2000 ft (610 m) to 4500 ft
(1372 m) above sea level.
For natural gas applications, gas pressure at unit gas connec-
tion must not be less than 4 in. wg (996 Pa) or greater than
13 in. wg (3240 Pa) while the unit is operating. On 48HCF/N/
T*05-06 (high-heat) units, the gas pressure at unit gas connec-
tion must not be less than 5 in. wg (1245 Pa) or greater than
13 in. wg (3240 Pa) while the unit is operating. See Table 3.
For liquefied petroleum applications, the gas pressure must not
be less than 11 in. wg (2740 Pa) or greater than 13.6 in. wg
(3390 Pa) at the unit connection.
The gas supply pipe enters the unit at the burner access panel
on the front side of the unit, through the long slot at the bottom
of the access panel. The gas connection to the unit is made to
the 1 / -in. FPT gas inlet port on the unit gas valve.
2
Manifold pressure is factory-adjusted for natural gas fuel use.
Adjust as required to obtain best flame characteristics. See
Table 4.
Table 3 — Natural Gas Supply Line Pressure Ranges
UNIT MODEL
48HCD/E/L/M/S/R
48HCF/N/T
(High Heat Units Only)
Table 4 — Natural Gas Manifold Pressure Ranges
UNIT MODEL
48HCD/E/L/M/S/R
48HCF/N/T
(High Heat Units Only)
CAUTION
EQUIPMENT DAMAGE
Failure to follow this caution may result in equipment damage.
When connecting the gas line to the unit gas valve, the in-
staller 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 size smaller than
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: hori-
zontally 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
UNIT SIZE MIN. MAX.
4.0 in. wg 13.0 in. wg
04, 05, 06
(996 Pa) (3240 Pa)
5.0 in. wg 13.0 in. wg
05, 06
(1245 Pa) (3240 Pa)
UNIT SIZE HIGH FIRE LOW FIRE
3.5 in. wg 1.7 in. wg
04, 05, 06
(872 Pa) (423 Pa)
3.5 in. wg 1.7 in. wg
05, 06
(872 Pa) (423 Pa)
1 / -in. Size the
2
kit installation instructions for details on these installation
methods. Observe clearance to gas line components per
Fig. 17.
9" MINIMUM CLEARANCE
FOR PANEL REMOVAL
BASE UNIT
BASE RAIL
ROOF
CURB
FROM
GAS
METER
LEGEND
National Fuel Gas
NFGC —
Code
STEEL PIPE NOMINAL DIAMETERS
(IN.)
1 /
2
3 / or 1
4
1- 1 / or larger
4
Fig. 17 — Gas Piping Guide
(with Accessory Thru-the-Curb Service Connections)
FACTORY-OPTION THRU-BASE CONNECTIONS (GAS
CONNECTIONS)
This service connection kit consists of a
er fitting (brass), a / -in. electrical bulkhead connector and a
1
2
3 / -in. electrical bulkhead connector, all factory-installed in the
4
embossed (raised) section of the unit basepan in the condenser
section. See Fig. 18.
BRASS FITTING FOR 3 TO 6 TON UNITS.
Fig. 18 — Thru-Base Gas 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.
Install a 1 / -in. NPT street elbow on the thru-base gas fitting.
2
Attach a 1 / -in. pipe nipple with minimum length of 16-in.
2
(406 mm) (field-supplied) to the street elbow and extend it
through the access panel at the gas support bracket. See
Fig. 19.
13
X
GAS
*
REGULATOR
MANUAL GAS
SHUTOFF VALVE *
48" MINIMUM
DRIP LEG
*
PER NFGC
FIELD-FABRICATED
SUPPORT *
*Field supplied.
NOTE: Follow all local codes.
SPACING OF SUPPORTS
X DIMENSION (FT.)
6
8
10
1 / -in. NPT gas adapt-
2
LOW VOLTAGE
CONDUIT
CONNECTOR
HIGH VOLTAGE
CONDUIT
CONNECTOR