Carrier 50TC Units without Thru-Base Connections, Field Control Wiring, Thermostat

50TC

Check tightness of connector lock nuts before connecting electrical conduits.

Field-supplied and field-installed liquidtight conduit connectors and conduit may be attached to the connectors on the basepan. Pull correctly rated high voltage and low voltage through appropriate conduits. Connect the power conduit to the internal disconnect (if unit is so equipped) or to the external disconnect (through unit side panel). A hole must be field cut in the main control box bottom on the left side so the 24-v control connections can be made. Connect the control power conduit to the unit control box at this hole.

Units without Thru-Base Connections —

1.Install power wiring conduit through side panel open- ings. Install conduit between disconnect and control box.

2.Install power lines to terminal connections as shown in Fig. 18.

All Units —

Voltage to compressor terminals during operation must be within voltage range indicated on unit nameplate. On 3-phase units, voltages between phases must be balanced within 2% and the current within 10%. Use the following formula to determine the percent of voltage imbalance.

max voltage deviation from average voltage

% Voltage Imbalance = 100 x

average voltage

C09103

Operation on improper line voltage or excessive phase imbalance constitutes abuse and may cause damage to electrical components. Such operation would invalidate any applicable Carrier warranty.

Field Control Wiring —

The 50TC unit requires an external temperature control device. This device can be a thermostat (field-supplied) or a PremierLink controller (available as factory-installed option or as field-installed accessory, for use on a Carrier Comfort Network or as a stand alone control) or the RTU-MP Controller for Building Management Systems using non-CCN protocols (RTU-MP is available as a factory-installed option only).

Thermostat —

Install a Carrier-approved accessory thermostat according to installation instructions included with the accessory. For complete economizer function, select a two-stage cooling thermostat. Locate the thermostat accessory on a solid wall in the conditioned space to sense average temperature in accordance with the thermostat installation instructions.

If the thermostat contains a logic circuit requiring 24-v power, use a thermostat cable or equivalent single leads of different colors with minimum of seven leads. If the thermostat does not require a 24-v source (no “C” connection required), use a thermostat cable or equivalent with minimum of six leads. Check the thermostat

installation instructions for additional features which might require additional conductors in the cable.

For wire runs up to 15 m (50 ft.), use no. 18 AWG (American Wire Gage) insulated wire (35_C minimum). For 15 to 23 m (50 to 75 ft.), use no. 16 AWG insulated wire (35_C minimum). For over 23 m (75 ft.), use no. 14 AWG insulated wire (35_C minimum). All wire sizes larger than no. 18 AWG cannot be directly connected to the thermostat and will require a junction box and splice at the thermostat.

		Central
Typical		Terminal
		Board
Thermostat
Connections
	X	X
C	C	C
G	G	G
W2	W2	W2
	(Note 3)
W1	W1	W1
O/B/Y2	Y2	Y2
(Note 1)	(Note 2)
Y1	Y1	Y1
R	R	R
	T–STAT

Note 1: Typical multi-function marking. Follow manufacturer’s configuration instructions to select Y2.

Note 2: Y2 to Y2 connection required on single-stage cooling units when integrated economizer function is desired

Note 3: W2 connection not required on units with single-stage heating. Field Wiring

C09459

Fig. 20 - Typical Low-Voltage Control Connections

Unit without thru-base connection kit —

Pass the thermostat control wires through the hole provided in the end panel (see item “D” in the view labeled “LEFT” in Fig. 1 and Fig. 2); then feed the wires through the raceway built into the corner post to the control box. Pull the wires over to the terminal strip on the upper-left corner of the Central Terminal Board. (CTB) See Fig. 21.

NOTE: If thru-the-bottom connections accessory is used, refer to the accessory installation instructions for information on routing power and control wiring.

Heat Anticipator Settings —

Set heat anticipator settings at 0.14 amp for the first stage and 0.14 amp for second-stage heating, when available.

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