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

50HCQA

LOW VOLTAGE

CONDUIT

CONNECTOR

HIGH VOLTAGE

CONDUIT

CONNECTOR

C08637

Fig. 20 - Thru-Base Connection Fittings

Field-supplied and field-installed liquid-tight 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

electronic thermostat, configure it for “non-heat pump” operation. 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 50 ft. (15 m), use no. 18 AWG (American Wire Gage) insulated wire (35_C minimum). For 50 to 75 ft. (15 to 23 m), use no. 16 AWG insulated wire (35_C minimum). For over 75 ft. (23 m), 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.

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. 16.

All Units: Voltage to compressor terminals during operation must be within voltage range indicated on unit nameplate. See Table 10. On 3-phase units, voltages between phases must be balanced within 2% and the

Typical

Thermostat

Connections

C

G

W2

(Note 2)

W1

O/B/Y2

(Note 1)

Y1

Central

Terminal

Board

X

C

T

GH E

W2	R
	M
	O
W1
	S
	T
Y2
	A
	T
Y1

current within 10%. Use the formula shown in the legend for Table 10, Note 2 (see page 42) to determine the percent of voltage imbalance. 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 50HCQA 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 2 stage Cooling/Heating thermostat according to installation instructions included with the accessory. The 50HCQ models do not require a thermostat with an O function to control the reversing valve operation. If using an

R R

Note 1: Typical multi-function marking. Follow manufacturer’s configuration instructions to select Y2. Do not configure for O output.

Note 2: W2 connection not required on units without electric heating.

Field Wiring

C09012

Fig. 21 - Typical Low-Voltage Control Connections

Unit without Thru-Base Connection Kit —

Pass the thermostat control wires through the hole provided in the corner post; 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. 22.

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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