Carrier 50PSW036-360 Wire Low Voltage Connections, Pre-Start-Up, Typical Field Wiring

L1 L2 L3

Grnd Power Distribution

Block Transformer

Connector

Low Voltage

C Control #1

Contactor -CC1 Contactor -CC2

Connector

Low Voltage

C Control #2

Fig. 8 — Typical Field Wiring

EXTERNAL LOOP POWER CONNECTION — If the unit is to be connected to an external loop pump or flow controller, connect the pump to the loop pump terminal block PB1. The maximum power handling is 4 amps at 240-v. The pumps will automatically cycle as required by the unit.

220-V OPERATION — All 220/240-v units are factory wired for 220-v. The transformers may be switched to 240-v operation (as illustrated on the wiring diagram) by switching the red (220-v) wire with the orange (240-v) wire at the L2 terminal.

380-VOLT OPERATION — All 380/415 volt units are factory wired for 420 volts. The transformers may be switched to 380-volt operation by switching the brown (380 volt) wire with the violet (420 volt) wire at the L1 terminal.

Step 7 — Wire Low Voltage Connections

THERMOSTAT CONNECTIONS

The thermostat should be wired directly to the Aquazone™ control board. See Fig. 4-7.

WATER FREEZE PROTECTION — The Aquazone control allows the field selection of source fluid freeze protection points through jumpers. The factory setting of jumper JW3 (FP1) is set for water at –1.1 C. In earth loop applications, jumper JW3 should be clipped to change the setting to –12.2 C when using antifreeze in colder earth loop applications. See Fig. 9.

Fig. 9 — Typical Aquazone Control Board

Jumper Locations (Complete C Control Shown)

ACCESSORY CONNECTIONS — The terminal labeled A on the control is provided to control accessory devices such as water valves, electronic air cleaners, humidifiers, etc. This sig- nal operates with the compressor terminal. See Fig. 10. Refer to the specific unit wiring schematic for details.

Terminal Strip

C

Typical

24 VAC Water

Valve

A

Fig. 10 — Typical Aquazone Accessory Wiring

(Deluxe D Control Shown)

NOTE: The A terminal should only be used with 24-v signals, not line voltage signals.

IMPORTANT: Two-compressor units with Complete C or Deluxe D controls wired to terminal A will be turned off if the controls are in lockout mode, even if the other board is in normal operating mode.

WATER SOLENOID VALVES — Water solenoid valves may be used on variable flow systems and ground water instal- lations. A typical well water control valve wiring which can limit waste water in a lockout condition is shown in Fig. 10. A slow closing valve may be required to prevent water hammer. When using a slow closing valve, special wiring conditions need to be considered. The valve takes approximately 60 sec- onds to open (very little water will flow before 45 seconds) and it activates the compressor only after the valve is completely opened by closing its end switch. When wired as shown, the valve will have the following operating characteristics:

1.Remain open during a lockout.

2.Draw approximately 25 to 35-va through the “Y” signal of the thermostat.

IMPORTANT: This can overheat the anticipators of electromechanical thermostats. Only use relay based electronic thermostats.

PRE-START-UP

System Checkout — When the installation is complete, follow the system checkout procedure outlined below before starting up the system. Be sure:

1.Voltage is within the utilization range specifications of the unit compressor and fan motor, and voltage is balanced for 3-phase units.

2.Fuses, breakers and wire are correct size.

3.Low voltage wiring is complete.

4.Piping and system flushing is complete.

5.Air is purged from closed loop system.

6.System is balanced as required. Monitor if necessary.

7.Isolation valves are open.

8.Water control valves or loop pumps are wired.

9.Transformer switched to lower voltage tap if necessary.

10.Service/access panels are in place.

11.Control field-selected settings are correct.

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