Carrier WEATHERMAKER 48/50AJ Operation And Service Manual

Also see for 48AJ: Installation, Start-Up and Service Instructions Installation instructions Started guide Operating and service guide

Contents

124BOARD ADDRESSES — Each board in the system has anaddress. The MBB has a default address of 1 but it does havean instance jumper that should be set to 1 as shown in Fig. 26.For the other boards in the system there is a 4-dip switch head-er on each board that should be set as shown below.0 = On; 1 = OffFIELD CONNECTION TERMINAL STRIPS — Field con-nection terminal strips are located in the main control box. SeeFig. 32 and Table 122.Accessory Control Components — In addition tothe factory-installed options, the units can also be equippedwith several field-installed accessories that expand the controlfeatures of the unit. The following hardware components canbe used as accessories.ROOM THERMOSTATS (48/50AJ,AW,A2,A4 UNITSONLY) — The ComfortLink™ controls support a conven-tional electro-mechanical or electronic thermostat that uses theY1, Y2, W1, W2, and G signals. The control also supports anadditional input for an occupied/unoccupied command that isavailable on some new thermostats. The ComfortLink controlscan be configured to run with multiple stages of capacity whichallows up to 6 stages of capacity. Although the unit can be con-figured for normal 2-stage control, it is recommended that themulti-stage control be used. The room thermostat is connectedto TB4.SPACE SENSOR — The ComfortLink controls support theuse of space temperature sensors. The T55 and T56 sensorsand CCN communicating T58 room sensor can be used. TheT55 and T56 sensors are connected to TB5 terminal 3, 4, and 5.The T58 sensor is connected to the CCN connections on TB3.When a T55, T56, or T58 sensor is used, the user must installthe red jumpers from R to W1, and W2 on TB4 for the heatfunction to work correctly.SPACE CO 2 SENSORS — The ComfortLink controls alsosupport a CO2 IAQ sensor that can be located in the space foruse in demand ventilation. The sensor must be a 4 to 20 mAsensor and should be connected to TB5 terminal 6 and 7. SeeFig. 33 for sensor wiring.ECONOMIZER HUMIDITY CHANGEOVER SEN-SORS — The ComfortLink controls support 5 differentchangeover schemes for the economizer. These are:• outdoor air dry bulb• differential dry bulb• outdoor air enthalpy curves• differential enthalpy• custom curves (a combination of an enthalpy/dewpointcurve and a dry bulb curve).The units are equipped as standard with an outside air andreturn air dry bulb sensor which supports the dry bulb change-over methods. If the other methods are to be used, then a field-installed humidity sensor must be installed for outdoor air en-thalpy and customer curve control and two humidity sensorsmust be installed for differential enthalpy. Installation holes arepre-drilled and wire harnesses are installed in every unit forconnection of the humidity sensors. The ComfortLink controlsconvert the measured humidity into enthalpy, dewpoint, andthe humidity changeover curves.MOTORMASTER ® V CONTROL — For operation below32 F when an economizer is not used, the units can be equippedwith an accessory Motormaster V control, which controls thespeed of the stage 1 condenser fans. The Motormaster V controlis a 3-phase inverter that controls the speed of the fans based ona pressure transducer connected to the liquid line. On 48/50A020-035 units, one fan will be controlled. On 48/50A036-060 units, two fans will be controlled. For units equipped withan economizer, there should not be a need for this control be-cause the economizer can provide free cooling using outside air,which will be significantly lower in operating cost.The accessory Motormaster V speed control is a completelyself-contained control and is not controlled by the unit’sComfortLink controller. On 48/50A051 and 060 units with 6fan motors, the Motormaster control configuration (M.M.)must be set to YES. See page 39.ACCESSORY NAVIGATOR™ DISPLAY — The accesso-ry handheld Navigator display can be used with the 48/50A se-ries units. See Fig. 34. The Navigator display operates the sameway as the scrolling marquee device. The ECB1 and ECB2boards contain a second LEN port (J3 connection) than can beused with the handheld Navigator display.CONTROL MODULE COMMUNICATIONSRed LED — Proper operation of the control boards can bevisually checked by looking at the red status LEDs as shown onFig. 26-29. When operating correctly, the red status LEDsshould blink in unison at a rate of once every 2 seconds. If thered LEDs are not blinking in unison, verify that correct power isbeing supplied to all modules. Also, be sure that the main baseboard is supplied with the current software. If necessary, reloadcurrent software. If the problem still persists, replace the MBB.A board LED that is lit continuously or blinking at a rate of onceper second or faster indicates that the board should be replaced.BOARD SW1 SW2 SW3 SW4ECB1 0 0 0 0ECB2 1 0 0 0SCB 0 0 0 0CEM 0 0 0 01 3 5 7 9 11 13 152 4 6 8 10 12 14 161 2 3 4 5 6 7 8R Y1 Y2 W1 W2 G C X1 3 5 7 9 11 13 152 4 6 8 10 12 14 16TB5TB6TB3TB4CLEN CCN CCN+ - GRDFig. 32 — Field Connection Terminal Strips (Main Control Box)A48-7081