Carrier 50CR Installation Instructions Manual

Also see for Infinity 50CR Series: Owner's information manual

Contents

16GROUND SCREW(IN SPLICE BOX)BLUYELBLKGROUNDLEADSINGLE-PHASECONNECTIONSTO DISCONNECTPER NEC3-PHASECONNECTIONSLEGENDNEC – National Electrical CodeField WiringSplice ConnectionsNOTE: Use copper wire only.L1L3L2C99057Fig. 17 -- Line Power ConnectionsA05303Fig. 18 -- Control PlateThe low--voltage circuit is fused by a board--mounted automotivefuse placed in series with transformer SEC1 and R circuit. The Ccircuit of transformer circuit is referenced to chassis ground througha printed circuit run at SEC2 and metal control board mountingeyelets. Check to be sure control board is mounted securely usingboth factory--installed screws.ACCESSORY INSTALLATIONA. Accessory Electric HeatersElectric heaters may be installed in 50CR per instructions suppliedwith electric heater package. See unit rating plate forfactory--approved electric heater kits.NOTE: Units installed without electric heat should have afactory--supplied sheet metal block--off plate installed over heateropening. This reduces air leakage and formation of exteriorcondensation.B. Outdoor Air Thermistor (OAT)A 2--screw terminal strip is provided for connection of an outdoortemperature thermistor. This strip is marked OAT.NOTE: While the installation of an outdoor temperature sensorusing the Infinity control board OAT terminals is optional, certainInfinity features (ComfortHeat, electric heat lockout, auto humiditycontrol) will be lost.OAT input is used to supply outdoor temperature data for systemlevel functions and for temperature display on User Interface.Using two wires of field--supplied thermostat wire cable, wire onelead of thermistor to one screw terminal and the other lead toremaining screw terminal; there is no polarity to be observed. It isstrongly recommended that two wires be used to connect thethermistor to eliminate noise interference in temperature reading. Ifthere are not two spare wires available in cable, one wire may beused to connect thermistor to OAT screw terminal 1 and the otherlead of the thermistor can be wired to 24--vac COM (C) wire. OATscrew terminal 1 is terminal located closest to the ABCD systemcommunications and is marked with a small number 1 next to theterminal strip.NOTE: Mis--wiring OAT inputs will not cause damage to eitherInfinity control or thermistor. If the thermistor is wired incorrectly,no reading will appear at User Interface. Re--wire thermistorcorrectly for normal operation.C. Humidifier ConnectionsThe Infinity control board terminal marked HUM is provided forlow voltage (24--vac) control of a humidifier. No humidistat isrequired as User Interface monitors indoor humidity. Whencommanded to operate humidifier, the unit control will energize theHUM output to turn humidifier on and de--energize HUM output toturn humidifier off. Wire HUM and C terminals directly tohumidifier as shown in Fig. 14.SPECIAL PROCEDURES FOR 208--V OPERATIONBe sure unit disconnect switch is open.Disconnect the yellow primary lead from the transformer. See unitwiring label. (See Fig. 15, 16 and 18)Connect the yellow primary lead to the transformer terminal labeled200--v.50CR