Carrier SINGLE PACKAGE ROOFTOP UNITS 48PG20-28 Installation And Service Instructions Manual

Also see for 48PG20---28: User's information manual User's information manual Controls, start-up, operation, service and troubleshooting instructions

Carrier SINGLE PACKAGE ROOFTOP UNITS 48PG20-28 Installation And Service Instructions Manual Manual pdf 39 page image

39Table 26 — Accessory/FIOP Static Pressure (in. wg)* — 48PG20-28LEGEND*The static pressure must be added to the external static pressure. The sum and the evaporatorentering-air cfm should then be used in conjunction with the Fan Performance tables to deter-mine blower rpm and watts.Table 27 — Fan Rpm at Motor Pulley Settings*LEGEND *Approximate fan rpm shown.NOTE: Factory pulley speed setting is at 3 turns open.Optional EconoMi$er IV — See Fig. 23 for EconoMi$erIV component locations. The optional EconoMi$er IV comesfrom the factory fully wired and assembled. No field wiring orassembly is required for standard outdoor dry bulb changeoveroperation. Field wiring of accessory sensors is required fordifferent operational modes.ECONOMI$ER IV STANDARD SENSORSOutdoor Air Temperature (OAT) Sensor — The outdoor airtemperature sensor is a 10 to 20 mA device used to measure theoutdoor-air temperature. The outdoor-air temperature is used todetermine when the EconoMi$er IV can be used for freecooling. The sensor is factory-installed on the EconoMi$er IVin the outdoor airstream. See Fig. 24. The operating range oftemperature measurement is 40 to 100 F.Mixed-Air Temperature (MAT) Sensor — The mixed-airtemperature sensor is a 3 K thermistor located at the outlet ofthe indoor fan. See Fig. 24. This sensor is factory installed. Theoperating range of temperature measurement is 0° to 158 F.The temperature sensor is a short probe with blue wiresrunning to it.Outdoor Air Lockout Sensor — The Economi$er IV isequipped with an ambient temperature lockout switch locatedin the outdoor airstream which is used to lock out the compres-sors below a 42 F ambient temperature.ECONOMI$ER IV CONTROLLER WIRING AND OPER-ATIONAL MODES — Determine the EconoMi$er IV controlmode before set up of the control. Some modes of operation mayrequire different sensors. Refer to Table 28. The EconoMi$er IVis supplied from the factory with a mixed-air temperaturesensor and an outdoor air temperature sensor. This allows foroperation of the EconoMi$er IV with outdoor air dry bulbchangeover control. Additional accessories can be added toallow for different types of changeover control and operationof the EconoMi$er IV and unit.Outdoor Dry Bulb Changeover — The standard controller isshipped from the factory configured for outdoor dry bulbchangeover control. The outdoor air and mixed-air temperaturesensors are included as standard. For this control mode, the out-door temperature is compared to an adjustable set point selectedon the control. If the outdoor-air temperature is above the setpoint, the EconoMi$er IV will adjust the outdoor-air dampers tominimum position. If the outdoor-air temperature is below theset point, the position of the outdoor-air dampers will be con-trolled to provided free cooling using outdoor air. When in thismode, the LED next to the free cooling set point potentiometerwill be on. The changeover temperature set point is controlledby the free cooling set point potentiometer located on the con-trol. The scale on the potentiometer is A, B, C, and D. SeeFig. 25 for the corresponding temperature changeover values.COMPONENT CFM4,000 4,500 5,000 5,500 6,000 6,500 7,000 7,500 8,000Economizer 0.02 0.03 0.04 0.05 0.06 0.07 0.08 0.09 0.10COMPONENT CFM8,500 9,000 9,500 10,000 10,500 11,000 11,500 12,000Economizer 0.11 0.12 0.13 0.15 0.16 0.17 0.19 0.20FIOP — Factory-Installed OptionUNIT48PG DRIVE MOTOR PULLEY TURNS OPEN0 1/2 1 1 1/ 2 2 2 1/ 2 3 3 1/2 4 4 1/2 5 5 1/2 620 and 24(230 and 460 volt)Low 685 706 727 749 770 791 812 833 854 876 897 918 939Mid-Low 949 970 992 1013 1035 1056 1078 1099 1120 1142 1163 1185 1206Mid-High 941 961 980 1000 1019 1039 1059 1078 1098 1117 1137 1156 1176High 1014 1038 1061 1085 1108 1132 1156 1179 1203 1226 1250 1273 1297Low n/a n/a n/a n/a n/a n/a n/a n/a n/a n/a n/a n/a n/aMid-Low 896 924 951 979 1006 1034 1062 1089 1117 1144 1172 1199 1227Mid-High 1113 1138 1163 1188 1213 1238 1264 1289 1314 1339 1364 1389 1414High 1096 1116 1137 1157 1177 1197 1218 1238 1258 1278 1299 1319 133920 and 24(575 volt)Low 751 768 785 802 819 836 853 869 886 903 920 937 954Mid-Low 949 970 992 1013 1035 1056 1078 1099 1120 1142 1163 1185 1206Mid-High 941 961 980 1000 1019 1039 1059 1078 1098 1117 1137 1156 1176High 1014 1038 1061 1085 1108 1132 1156 1179 1203 1226 1250 1273 1297Low n/a n/a n/a n/a n/a n/a n/a n/a n/a n/a n/a n/a n/aMid-Low 873 893 912 932 951 971 991 1010 1030 1049 1069 1088 1108Mid-High 1113 1138 1163 1188 1213 1238 1264 1289 1314 1339 1364 1389 1414High 1096 1116 1137 1157 1177 1197 1218 1238 1258 1278 1299 1319 133928(all voltages)Low 687 703 718 734 749 765 780 796 811 827 842 858 873Mid-Low 805 822 839 856 872 889 906 923 940 957 973 990 1007Mid-High 941 961 980 1000 1019 1039 1059 1078 1098 1117 1137 1156 1176High 1014 1038 1061 1085 1108 1132 1156 1179 1203 1226 1250 1273 1297Low 687 703 718 734 749 765 780 796 811 827 842 858 873Mid-Low 805 822 839 856 872 889 906 923 940 957 973 990 1007Mid-High 941 961 980 1000 1019 1039 1059 1078 1098 1117 1137 1156 1176High 1014 1038 1061 1085 1108 1132 1156 1179 1203 1226 1250 1273 1297n/a — not available