Carrier 48LC Series Controls, Start-up, Operation And Troubleshooting

Also see for 48LC 05: Controls, Start-Up, Operation and Troubleshooting Service and maintenance instructions Service and maintenance instructions

Contents

Carrier 48LC Series Controls, Start-up, Operation And Troubleshooting Manual pdf 6 page image

6SCROLL +-NAVIGATE/EXITMODIFY/SELECTPAGEC06322Fig. 4 -- System Pilott User InterfaceForce HierarchyThere is a hierarchy in SystemVu controls with regards to forcing apoint. Programs and devices write a force at different prioritylevels. A higher level (smaller number, 1 being the highest) willoverride a lower level force. The SystemVu controller uses aControl Force at level 7. The Navigatort device writes a ServiceForce which is level 3. System Pilott and Touch Pilott deviceswrite Supervisor Forces at level 4. Network programs can be set towrite different level priority forces.NOTE: In the case of a control power reset, any force in effect atthe time of power reset will be cleared.IMPORTANT: All further discussions and examples in thisdocument will be based on the SystemVut controller.START-UPIMPORTANT: Do not attempt to start unit, even momentarily,until all items on the Start--Up Checklist (see page 163) and thefollowing steps have been read/completed.Unit PreparationCheck that unit has been installed in accordance with theseinstallation instructions and all applicable codes.Refrigerant Service PortsThe refrigerant system has a total of 3 Schrader-type service gaugeports per circuit. One port is located on the suction line, one on thecompressor discharge line, and one on the liquid line. Be sure thatcaps on the ports are tight.Crankcase HeaterThe compressor is equipped with a crankcase heater. There is a controlfunction used to turn the crankcase heaters on and off when thecompressor is not running. This is a configurable value for which thefactory default value is set to 65_F. If the ambient is above the selectedvalue the control will prevent the crankcase heater from turning on.IMPORTANT: Unit power must be on for 24 hours prior tostart--up to allow the crankcase heater to run. Otherwise, damage tothe compressor may result.Compressor RotationUNIT DAMAGE HAZARDFailure to follow this caution may result in unit damage.Improper wiring will cause compressor stoppage and alarm.Correct wiring by switching leads as indicated below.CAUTION!On 3-phase units, it is important to be certain the compressors arerotating in the proper direction. To determine whether or notcompressors are rotating in the proper direction, use a phase-rotationmeter on the unit input power to check for L1-L2-L3 or clockwiserotation or use the Service Test mode to energize a compressor. If thecompressor is rotating in the wrong direction, the controls will stop thecompressor and display alarm for “Circuit A Reverse Rotation”.NOTE: Indoor or outdoor fan rotation direction may not indicateproper input power phase sequence, as some 3-phase units usesingle-phase fan motors.To correct the wrong compressor rotation direction, perform thefollowing procedure:1. Turn off power to the unit and lock out the power.2. Switch any two of the incoming unit power leads.3. Turn on power to the unit.4. Verify corrected compressor rotation.Power SupplyAll 208/230-v units are factory wired for 230-v power supply. Ifthe 208/230-v unit is to be connected to a 208-v power supply, thetransformers must be rewired by moving the wire from the230-volt connection and moving to the 200-volt terminal on theprimary side of the transformer. Refer to unit label diagram foradditional information.Internal WiringCheck all electrical connections in unit control boxes; tighten asrequired.Evaporator FanThe evaporator fan should be checked and may need to be adjustedfor specific applications. The unit will have a belt drive motorpowered by a Variable Frequency Drive (VFD). Refer to the unitproduct data for Fan Performance tables and physical data.The fan belt and variable pulleys are factory installed and set, but mayneed to be adjusted for specific applications. Check the fan to ensureits rotation is in the proper direction before adjusting performance. Toalter fan performance, first adjust the pulley settings to provide theapplication’s full load design air flow when running at the IDFMaximum Fan Speed (MAXIMUM IDF SPEED). The unitoperating speeds can then be adjusted with Free Cooling IDF Speed(FREE COOL IDF SPEED), High Cooling IDF Speed (HIGHCOOL IDF SPEED), Medium Cooling IDF Speed (MED COOLIDF SPEED), Low Cooling IDF Speed (LOW COOL IDFSPEED), Heating IDF Speed (HEATING IDF SPEED), andVentilation Only IDF Speed (VENT IDF SPEED). Set the indoor fanpulley to the greater application design point CFM for heating orcooling and equal to 100% fan speed. Adjust the Heating Fan Speedand High Cooling Fan Speed so that the CFM is not lower than theminimum CFM allowed in the product data. If the exact CFM cannotbe set by the half turn pulley settings then adjust the IDF MaximumFan Speed (MAXIMUM IDF SPEED) to fine tune the CFM to theapplication requirements. The VFD’s settings should not be used foradjusting fan performance. Specific VFD information can be found inthe major components section.