Carrier WeatherMaker 48A020 Installation Instructions Manual

Also see for WeatherMaker 48A020: Installation and operating instructions Installation instructions

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Carrier WeatherMaker 48A020 Installation Instructions Manual Manual pdf 24 page image

24Step 9 — Make Electrical ConnectionsPOWER WIRING — Units are factory wired for the voltageshown on the unit nameplate.Provide a unit safety disconnect switch in the main power supplyto each unit (see Fig. 23). Select switch size and mounting loca-tion in accordance with applicable local codes or National Electri-cal Code (NEC). If combining the functions of safety disconnectwith maximum overcurrent protection (MOCP) fuses (“fused dis-connect”), coordinate safety switch size with MOCP size data asmarked on unit informative plate.Unit may be equipped with optional factory-installed non-fuseddisconnect switch (see Fig. 23). Provide maximum overcurrentprotection devices (fuses or HACR breakers, per local codes) inbranch circuit wiring remote from unit. Observe requirements ofNEC Article 440. Install service switch upstream of remote fusesif required.The main power terminal block is suitable for use with aluminumor copper wire. See Fig. 23. Units have circuit breakers for com-pressors, fan motors, and control circuit. The unit must be electri-cally grounded in accordance with local codes or, in absence oflocal codes, with NEC, ANSI C1-latest year.FIELD POWER SUPPLY — Unit is factory wired for voltageshown on unit nameplate.Field wiring can be brought into the unit from bottom (throughbasepan and roof curb) or through side of unit (corner post next tocontrol box).A 3 1 /2 -in. NPT coupling for field power wiring and a 3 /4-in.NPT coupling for 24-v control wiring are provided in basepan.In the side post, there are two 2 1/2-in. (sizes 020-035) or 3-in.(sizes 040-060) knockouts for the field power wiring. SeeFig. 5-12. If control wiring is to be brought in through side ofunit, a 7/8 -in. diameter hole is provided in the condenser sidepost next to the control box.Do not route control wiring in the same conduit as power wiring.If disconnect box is mounted to corner post, be careful not to drillor screw into the condenser coil.Routing Through Bottom of Unit — If wiring is brought inthrough bottom of unit, use field-supplied watertight conduit toroute power wiring through the 31/2-in. diameter hole provided inthe unit basepan.Install conduit connector in unit basepan as shown in Fig. 5-12.Route power and ground lines through connector to terminal con-nections in unit control box as shown on unit wiring diagram andFig. 23.Use strain relief going into control box through 35/8-in. diameterhole provided. After wires are in unit control box, connect topower terminal block (see Power Wiring section).Low-voltage wiring must be run in watertight conduit from thebasepan to control box and through 7/8-in. diameter hole providedin bottom of unit control box. Field-supplied strain relief must beused going into the box. After wiring is in control box, make con-nections to proper terminals on terminal blocks (see Field ControlWiring section).Routing Through Side of Unit — Route power wiring in field-supplied watertight conduit into unit through 21/2-in. (sizes 020-035) or 3-in. (sizes 040-060) hole.Use field-supplied strain relief going into control box through 35⁄8-in. diameter hole provided. After wires are in unit control box,connect to power terminal block (see Power Wiring section).Bring low-voltage control wiring through the 7/8-in. diameter holeprovided in the condenser section side post. Use strain relief goinginto 7/8-in. diameter hole in bottom of unit control box.After wiring is in control box, make connection to proper termi-nals on terminal blocks (see Field Control Wiring section).Affix crankcase heater sticker (located in the installer’s packet) tounit disconnect switch.Voltage to compressor terminals during compressor operationmust be within the voltage range indicated on the unit nameplate.Phases must be balanced within 2%.Use the following formula to determine the percent of voltageimbalance.% Voltage Imbalance:Example: Supply voltage is 230-3-60Determine maximum deviation from average voltage.(AB) 227-224 = 3 v(BC) 231-227 = 4 v(AC) 227-226 = 1 vMaximum deviation is 4 v.Determine percent of voltage imbalance.LEGENDGND — GroundNEC — National Electrical CodeTB — Terminal BlockFig. 23 — Field Power Wiring Connectionsa48-6977FIELD SUPPLIEDDISCONNECT PER NEC FIELDPOWERSUPPLY11 2122231312TB1EQUIP GNDFIELD POWER WIRING 11 2122231312GNDOPTIONALFACTORY-INSTALLEDDISCONNECTFIELD-INSTALLED DISCONNECTFACTORY-INSTALLED DISCONNECTIMPORTANT: The VAV (variable air volume) units use vari-able frequency drives, which generate and can radiate radiofrequency energy. If units are not installed and used in accor-dance with these instructions, they may cause radio interfer-ence. They have been tested and found to comply with limitsof a Class A computing device pursuant to International Stan-dard in North American EN 61000-2/3, which are designed toprovide reasonable protection against such interference whenoperated in a commercial environment.WARNINGThe unit must be electrically grounded in accordance withlocal codes and NEC ANSI/NFPA 70 (National Fire Protec-tion Association). Personal injury may result.= 100 x max voltage deviation from average voltageaverage voltageAB = 224 vBC = 231 vAC = 226 vAverage Voltage = (224 + 231 + 226) = 681 = 2273 3A B CMOTOR