Carrier OMNIZONE 50BV020-064 Installation And Service Instructions Manual

Also see for OMNIZONE 50BV020: Operating and troubleshooting guide

Contents

30Table 11 — Thermistor Resistance vs TemperatureValues for Supply-Air Temperature Sensor(10 Kilo- ohm)SMOKE DETECTOR/FIRE ALARM SHUTDOWN(FSD) — To allow a smoke detector to shut the 50BV down,remove the jumper from FSD to C and wire these terminals to aset of normally closed contacts on the smoke detector.ALARM (ALARM) AND WARNING (WARN) OUT-PUTS — Two dry contacts output a discrete signal when thealarm and warning lights on the display are lit. To pick up thealarm output signal, wire between the ALARM and ALM-CMterminals. To pick up the warning output signal, wire betweenthe WARN and ALM-CM terminals.REMOTE OCCUPANCY (ROCC) — The 50BV unit maybe commanded by another control system or a twist timer tobecome occupied and run when a set of dry contacts close. Inorder for this to occur, wire the contacts to ROCC and C andset the Local/Off/Remote switch to REMOTE.RETURN AIR TEMPERATURE SENSOR (RAS) — Thereturn/mixed air temperature sensor is a 5 kiloohm temperaturesensor used as the space control point. For every degree thatthe RAS is below the set point, the supply air set point will bereset by the configured value in the custom configured RESETRATIO. Refer to Table 12 and Fig. 31.Table 12 — Thermistor Resistance vs TemperatureValues for Return-Air TemperatureSensor (5 kiloohm)Wire the sensor to PCB1 connector J3, terminals 15 and 16.Change custom configuration as instructed in Configure theCustom Programming Selections section. Changing this con-figuration to YES changes the EWT input to be used as returnair temperature input.START-UPGeneral — Complete the Start-Up Checklist on page CL-1before attempting system start-up.CRANKCASE HEATERS — The 50BVT,U,V,W,X034-064units include crankcase heaters. Crankcase heaters are ener-gized as long as there is power to the unit and the compressoris not operating.Wait 24 hours before starting the compressors to permitwarming by the crankcase heaters.AFTER 24 hours, continue with the procedures below.CONFIRM THE INPUT POWER PHASE SEQUENCE —The input power phase rotation sequence must be L1-L2-L3 =ABC (or forward or clockwise) as indicated with a phaserotation meter. Incorrect input phase rotation will cause the com-pressors to rotate in reverse, which results in no cooling capacity.If the compressor is rotating in the wrong direction, it may:emit increased noise; shut down due to internal overloadprotection; have only a small decrease in suction pressure whenit starts; or have only a small increase in discharge pressureTEMP TEMP RESISTANCE(C) (F) (Ohms)–40 –40 335,651–35 –31 242,195–30 –22 176,683–25 –13 130,243–20 –4 96,974–15 5 72,895–10 14 55,298–5 23 42,3150 32 32,6515 41 25,39510 50 19,90315 59 15,71420 68 12,49425 77 10,00030 86 8,05635 95 6,53040 104 5,32545 113 4,36750 122 3,60155 131 2,98560 140 2,48765 149 2,08270 158 1,752TEMP TEMP RESISTANCE(C) (F) (Ohms)–40 –40 167,835–35 –31 121,098–30 –22 88,340–25 –13 65,121–20 –4 48,487–15 5 36,447–10 14 27,648–5 23 21,1570 32 16,3255 41 12,69710 50 9,95215 59 7,85720 68 6,24725 77 5,00030 86 4,02835 95 3,26540 104 2,66245 113 2,18350 122 1,80155 131 1,49360 140 1,24465 149 1,04170 158 87675 167 74080 176 628IMPORTANT: On VAV units, fan rotation directioncan NOT be used for the phase sequence check; fanrotation for VAV units with a variable speed drive isindependent of the unit input wiring sequence.NOTE: All dimensions are in inches.Fig. 31 — Return Air Temperature Sensor(P/N HH79NZ079)a50-7274ef1.008.000.81 1.250.220.250.502.2565ºO0.187 O0.187(2 HOLES)