Carrier WeatherMaster 48HC04 Series Installation Instructions Manual

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13Step 11 — Install Gas PipingInstallation of the gas piping must be accordance with localbuilding 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 theCAN/CSA B149.1 and CAN/CSA B149.2 installation codesfor gas burning appliances.This unit is factory equipped for use with natural gas (NG) fuelat elevations up to 2000 ft (610 m) above sea level. Unit maybe 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 upto 2000 ft (610 m) above sea level. In U.S.A., the input rating foraltitudes above 2000 ft (610 m) must be derated by 4% for each1000 ft (305 m) above sea level. In Canada, the input rating mustbe 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 than13 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 than13 in. wg (3240 Pa) while the unit is operating. See Table 3.For liquefied petroleum applications, the gas pressure must notbe 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 panelon the front side of the unit, through the long slot at the bottomof the access panel. The gas connection to the unit is made tothe 1/ 2-in. FPT gas inlet port on the unit gas valve.Manifold pressure is factory-adjusted for natural gas fuel use.Adjust as required to obtain best flame characteristics. SeeTable 4.Install a gas supply line that runs to the unit heating section.Refer to the NFPA 54/NFGC or equivalent code for gas pipesizing data. Do not use a pipe size smaller than 1 /2-in. Size thegas supply line to allow for a maximum pressure drop of0.5 in. wg (124 Pa) between gas regulator source and unit gasvalve 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/underunit basepan (accessory kit required), or through unit basepan(factory option or accessory kit required). Consult accessorykit installation instructions for details on these installationmethods. Observe clearance to gas line components perFig. 17.Fig. 17 — Gas Piping Guide(with Accessory Thru-the-Curb Service Connections)FACTORY-OPTION THRU-BASE CONNECTIONS (GASCONNECTIONS)This service connection kit consists of a 1/ 2-in. NPT gas adapt-er fitting (brass), a 1 /2-in. electrical bulkhead connector and a3/ 4-in. electrical bulkhead connector, all factory-installed in theembossed (raised) section of the unit basepan in the condensersection. See Fig. 18.Fig. 18 — Thru-Base Gas Connection FittingsThe thru-base gas connector has male and female threads. Themale threads protrude above the basepan of the unit; the femalethreads protrude below the basepan.Check tightness of connector lock nuts before connecting gaspiping.Install a 1/2-in. NPT street elbow on the thru-base gas fitting.Attach a 1/2-in. pipe nipple with minimum length of 16-in.(406 mm) (field-supplied) to the street elbow and extend itthrough the access panel at the gas support bracket. SeeFig. 19.Table 3 — Natural Gas Supply Line Pressure RangesUNIT MODEL UNIT SIZE MIN. MAX.48HCD/E/L/M/S/R 04, 05, 06 4.0 in. wg(996 Pa)13.0 in. wg(3240 Pa)48HCF/N/T(High Heat Units Only) 05, 06 5.0 in. wg(1245 Pa)13.0 in. wg(3240 Pa)Table 4 — Natural Gas Manifold Pressure RangesUNIT MODEL UNIT SIZE HIGH FIRE LOW FIRE48HCD/E/L/M/S/R 04, 05, 06 3.5 in. wg(872 Pa)1.7 in. wg(423 Pa)48HCF/N/T(High Heat Units Only) 05, 06 3.5 in. wg(872 Pa) 1.7 in. wg(423 Pa)CAUTIONEQUIPMENT DAMAGEFailure 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 tothe valve.XBASE UNITBASE RAILROOFCURB9” MINIMUM CLEARANCEFOR PANEL REMOVALMANUAL GASSHUTOFF VALVE*GASREGULATOR*48” MINIMUMDRIP LEGPER NFGC*FIELD-FABRICATEDSUPPORT*FROMGASMETERLEGEND *Field supplied.NOTE: Follow all local codes.NFGC — National Fuel GasCodeSTEEL PIPE NOMINAL DIAMETERS(IN.)SPACING OF SUPPORTSX DIMENSION (FT.)1 / 2 63 / 4 or 1 81- 1/ 4 or larger 10LOW VOLTAGECONDUITCONNECTORHIGH VOLTAGECONDUITCONNECTORBRASS FITTING FOR 3 TO 6 TON UNITS.