Carrier 48HC 04-28 Controls, Start-up, Operation And Troubleshooting

Also see for /50HC 04-28: Manual

Contents

Carrier 48HC 04-28 Controls, Start-up, Operation And Troubleshooting Manual pdf 82 page image

8248/50HC 17-28 Units — Low Voltage TerminalBoards (TB A and TB B)There are two terminal boards with 16 terminals each, and ori-ented one mounted above the other. The front have screw ter-minals and the back have spade connectors. These terminalboards provide a connection point for the thermostat or spacesensor and for most field-installed accessories. See Table 33.Communication Interface Board (CIB)This circuit board provides a field connection point for unitcommunications. The Local Equipment Network (LEN) RJ-11connector allows a hand-held Navigator to be plugged in to ac-cess the unit’s menus. The Carrier Comfort Network® (CCN)RJ-11 connector or the CCN screw terminals allow buildingcommunication connections. See Fig. 35.Fig. 35 — Communications Interface Board (CIB)Central Terminal Board (CTB)This circuit board is a simple trace board that serves as a junc-tion point between components and the ComfortLink system. Itis the distribution center for transformer 1’s power. The inte-grated gas controller (IGC), electric heater control, compressorcontrol, and unit shutdown all feed through this trace board.See Fig. 36 and Table 34 for the connections through thisboard. Fig. 36 — Central Terminal Board (CTB)*Point name displayed on the scrolling marquee or Navigator™ display.1234LEN CCN CCN(+) (-)(com) shieldTable 33 — Upper and Lower Field Connection Terminal (TB A and TB B) Board Connections (17-28 Size Units)TERMINALBLOCKTERMINALLABELDISPLAYNAME* DESCRIPTION SENSORLOCATION TYPE OF I/O TERMINALNUMBERUpper(TB A)C- 2 Transformer 2 Common 24 VAC common 1,3,4R- 2 24 VAC power Transformer 2 24 VAC 13,15,16SPT+ SPT Space temperature (T55/56) space 10k thermistor 8SPT- SPT Space temperature (T55/56) space 10k thermistor 7SPTO SPTO Space temperature offset (T56) space 10k thermistor 5FDWN FDWN Fire shutdown switch input supply/return/space 24 VAC input 11X ALRM Alarm output (normally open) space 24 VAC output 2G G Thermostat G (Fan) space 24 VAC input 6W1 W1 Thermostat W1 (1st stage heat) space 24 VAC input 8W2 W2 Thermostat W2 (2nd stage heat) space 24 VAC input 10Y1 Y1 Thermostat Y1 (1st stage cool) space 24 VAC input 12Y2 Y2 Thermostat Y2 (2nd stage cool) space 24 VAC input 14Lower(TB B)RAT RAT Return Air Temperature Sensor return duct 10k thermistor 1,3SAT SAT Supply Air Temperature Sensor Blower or duct 10k thermistor 5,7HUM HUM Humidistat switch input supply/return/space switch input 9LPWR Analog Sensor Loop power(24vdc) 24 VDC 8COM Analog sensor common Ground 4IAQ IAQ Indoor air quality sensor return/space 4- 20 mA input 6SPRH SP.RH or OAQ Relative humidity sensor orOutdoor air quality sensor field installed 4-20 mA input 2RMOC RM.OC Remote occupancy switch field installed 24 VAC input 10ENTH ENTH or IAQ.S Outdoor enthalpy switch, orIndoor air quality switcheconomizer, orreturn/space 24 VAC input 12R- 2 24 VAC power Transformer 2 24 VAC 15C- 2 Transformer 2 Common 24 VAC common 16