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

Also see for 48FC 04: Installation instructions

Carrier 48FC Series Controls, Start-up, Operation And Troubleshooting Manual pdf 57 page image

57Protective DevicesCompressor ProtectionOvercurrentEach compressor has internal line break motor protection.OvertemperatureEach compressor has an internal protector to protect it againstexcessively high discharge gas temperatures.High--Pressure SwitchIf the high-pressure switch trips, the compressor will shut downand the Circuit A High Pressure Alert will activate. Refer to thealarm section for the High pressure alert.Evaporator Fan Motor ProtectionThe ECM motor is protected from locked rotor and over-currentprotection through the electronic control module attached to themotor.Condenser Fan Motor ProtectionThe motor is internally protected against overload.Saturated Suction Pressure (SSP)If the SSP for a particular circuit is reading below the alarm set pointfor an extended period of time, that circuit will be shut down. After 15minutes, the alarm will automatically reset. If this alarm occurs 3 timesconsecutively, the circuit will remain locked out until an alarm reset isinitiated via CCN or manually via the SystemVut controller display(see Alarms and Alerts section for more details).Condensate Overflow Switch (COFS)A separate factory installed device can detect a full drain pan. Thisdevice consists of a pan sensor to detect the water level and a relaycontrol switch to read the sensor. The control switch is located inthe supply fan section and feeds into the SystemVu control to trip acondensate overflow fault. The relay switch is a normally opendevice that closes when power is applied. If the sensor detects highwater levels for 10 seconds straight, it will open the contactremoving the input provided to the SystemVu control. The switchwill also turn its red LED on. If the water level is low enough for 5minutes the relay will close again applying the input back to theSystemVu controller. A blinking red LED on the switch indicatesthat the sensor has been disconnected.Space Mounted SensorsSpace Temperature Sensor (T--55)The T-55 space temperature sensor (part no. 33ZCT55SPT) is afield-installed accessory. The sensor is installed on a buildinginterior wall to measure room air temperature. The T-55 sensor alsoincludes an override button on the front cover to permit occupantsto override the Unoccupied Schedule (if programmed).TB5--1 Sensor Input. . . . . . . . . . . . .TB5--2 Sensor Common. . . . . . . . . . . . .Space Temperature Sensor (T--56)The T-56 space temperature sensor (part no. 33ZCT56SPT) is afield-installed accessory. This sensor includes a sliding scale on thefront cover that permits an occupant to adjust the space temperatureset point remotely. The T-56 sensor also includes an overridebutton on the front cover to allow occupants to override theunoccupied schedule (if programmed).TB5--1 Sensor Input. . . . . . . . . . .TB5--2 Sensor Common. . . . . . . . . . .TB5--3 Setpoint Offset Input. . . . . . . . . . .Space Temperature Sensor AveragingSee Fig. 31 for space temperature averaging with T-55 sensorsonly. If the use of one T-56 sensor is required, refer to Fig. 32.