66396-YIM-C-100412 Unitary Products GroupTHERMOSTATThe room thermostat should be located on an insidewall approximately 1422 mm (56”) above the floorwhere it will not be subject to drafts, sun exposure orheat from electrical fixtures or appliances. Follow man-ufacturer's instructions enclosed with thermostat forgeneral installation procedure. A minimum of sevencolor-coded insulated wires 1.0 mm2 (#18 AWG)should be used to connect thermostat to unit.POWER AND CONTROL WIRINGField wiring to the unit must conform to provisions ofthe National Electrical Code, ANSI / NFPA No. 70 (inU.S.A.), current Canadian Electrical Code C22.1 (inCanada) and/or local ordinances. The unit must beelectrically grounded in accordance with NEC and CEC(as specified above) and/or local codes. Voltage toler-ances, which must be maintained at the compressorterminals, during starting and running conditions, areindicated on the unit Rating Plate and the Unit Applica-tion Data table.The internal wiring harness furnished with this unit isan integral part of a CSA design certified unit. Fieldalteration to comply with electrical codes should not berequired.A fused disconnect switch should be field provided forthe unit. The switch must be separate from all other cir-cuits. Wire entry at knockout openings require conduitfittings to comply with NEC (in U.S.A.), CEC (in Can-ada) and/or local codes. Refer to the Unit DimensionsFigure 10 and Utilities Entry Data Table 12 for installa-tion location. If any of the wire supplied with the unitmust be replaced, replacement wire must be of thetype shown on the wiring diagram and the same mini-mum gauge as the replaced wire.Electrical line must be sized properly to carry the load.Use copper conductors only. Each unit must be wiredwith a separate branch circuit fed directly from themeter panel and properly fused.Refer to the Typical Field Wiring Figure 5 and to theappropriate unit wiring diagram for control circuit andpower wiring information.OPTIONAL ELECTRIC HEATThe factory-installed heaters are wired for single pointpower supply. Power supply need only be brought intothe single point terminal block and thermostat wiring tothe low voltage terminal strip located in the upper por-tion of the unit control box.These CSA approved heaters are located within thecentral compartment of the unit with the heater ele-ments extending into the supply air chamber. Refer toFigure 10 for access panel location.Fuses are supplied, where required, by the factory.Some KW sizes require fuses and others do not. Referto Table 3 for minimum CFM limitations and to Tables7, 8 and 9 for electrical data.When connecting electrical power and controlwiring to the unit, waterproof type connectorsMUST BE USED so that water or moisturecannot be drawn into the unit during normaloperation. The above waterproofing conditionswill also apply when installing a field-supplieddisconnect switch.TABLE 2: CONTROL WIRE SIZESWire Size Maximum Length 11. From the unit to the thermostat and back to the unit.18 AWG 45.72 meters (150 Feet)TABLE 3: ELECTRIC HEAT APPLICATION DATANOMINALHEATER SIZE(KW)VOLTAGE3-PHASE,50 HZMINIMUM m3/s (CFM) UNIT SIZE20 TON18380/415 2.9 (6000)365472