Carrier WeatherMaster 48HC07-12 Installation Instructions Manual

15Install 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 smaller than the size specified.Size the gas supply line to allow for a maximum pressure dropof 0.5-in. wg (124 Pa) between gas regulator source and unitgas valve connection when unit is operating at high-fire flowrate.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 unitbasepan (factory option or accessory kit required). Consult ac-cessory kit installation instructions for details on these installa-tion methods. Observe clearance to gas line components perFig. 15.Fig. 15 — Gas Piping Guide (with Accessory Thru-the-Curb Service Connections)FACTORY OPTION THRU-BASE CONNECTIONS(GAS CONNECTIONS) — This service connection kit con-sists of a NPT gas adapter fitting, an electrical bulkhead con-nector and a 3/4-in. electrical bulkhead connector, all factory-installed in the embossed (raised) section of the unit basepan inthe condenser section. See Fig. 16.Fig. 16 — Thru-Base Connection FittingsThe thru-base gas connector has male and female threads.The male threads protrude above the basepan of the unit; thefemale threads protrude below the basepan.Check tightness of connector lock nuts before connectinggas piping.Gas Line — Install a 1/2-in. (08 and 09 size Low Gas units on-ly) or 3/4-in. (for all other units) NPT street elbow on the thru-base gas fitting. Attach an appropriate size pipe nipple withminimum length of 16-in. (406 mm) (field-supplied) to thestreet elbow and extend it through the access panel at the gassupport bracket. See Fig. 17.Fig. 17 — Gas Line PipingOther hardware required to complete the installation of thegas supply line will include a manual shutoff valve, a sedimenttrap (drip leg) and a ground-joint union. A pressure regulatorvalve may also be required (to convert gas pressure frompounds to inches of pressure). The manual shutoff valve mustbe located within 6-ft (1.83 m) of the unit. The union, locatedin 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 beremoved for service. If a regulator valve is installed, it must belocated a minimum of 4-ft (1220 mm) away from the unit’sflue outlet. Some municipal codes require that the manual shut-off valve be located upstream of the sediment trap. See Fig. 18and Fig. 19 for typical piping arrangements for gas piping thathas been routed through the sidewall of the curb. See Fig. 20for typical piping arrangement when thru-base is used. Ensurethat all piping does not block access to the unit’s main controlbox or limit the required working space in front of the controlbox.Fig. 18 — Gas Piping with Thru-Curb AccessorySTEEL PIPE NOMINALDIAMETER (in.)SPACING OF SUPPORTS XDIMENSION (ft)1/2 63/4 or 1 811/4 or larger 10LEGENDNFGC — National Fuel Gas Code* Field supplied.NOTE: Follow all local codes.XBASE UNITBASE RAILROOFCURB9” MINIMUM CLEARANCEFOR PANEL REMOVALMANUAL GASSHUTOFF VALVE*GASREGULATOR*48” MINIMUMDRIP LEGPER NFGC*FIELD-FABRICATEDSUPPORT*FROMGASMETERLOW VOLTAGECONDUITCONNECTORHIGH VOLTAGECONDUITCONNECTORBRASS FITTING FOR 3 TO 6 TON UNITS.EMBOSSMENT BRASS FITTINGFOR 3-6 TON UNITSSUPPORTBRACKET9” (229mm) minUnionShut OffValveDripLegThru-Curb AdapterUnit Base Rail