Carrier 40VMU Series - Step 6 - Position and Connect Controller

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Step 6 — Position and Connect Controller
Wired controllers should be installed in a position that
maintains good temperature control:
• Position the thermostat approximately 48 in. above floor
level.
• Do not position thermostat where it can be directly
affected by the unit’s discharge airstream.
• Avoid external walls and drafts from windows and doors.
• Avoid positioning near shelves and curtains as these
restrict air movement.
• Avoid heat sources such as direct sunlight, heaters,
dimmer switches, and other electrical devices.
• See Fig. 16 for an example of communication wire
connection.
CONTROL WIRING
1. The communication wire should be 2-core stranded
shielded cable.
2. For indoor and outdoor unit communication, use P, Q
terminals. Shielded core should be used for ground.
3. Wiring should be run according to the wiring diagram.
4. Communication wire must not form a closed loop.
See Fig. 16.
Fig. 16 —Communication Wire Connection
OPTION/EXTENSIONS OF COMMUNICATION
WIRING — To extend control wiring or to make terminal
connections, use the PQE connection wire supplied in the
accessory kit and follow the steps below.
1. Cut the connector on the outdoor unit side as shown in
Fig. 17.
2. Strip a suitable length of the insulation layer as shown in
Fig. 18.
Fig. 18 —Stripping The Wire
3. Use a suitable screwdriver to fix the communication wire
on the outdoor unit communication terminal as shown in
Fig. 19.
Fig. 19 —Connecting Communication Wire to
Outdoor Unit Communication Terminal
If communication wires are used to connect indoor units, find
the corresponding port and plug it in directly as shown in Fig.
20.
Fig. 20 —Connecting the Communication Wires
If it is not possible to buy communication wires from Carrier,
connect the indoor unit side of communication wires using the
connector provided with the accessories as shown in Fig. 21.
See Figs. 22 and 23 for typical communication wiring of the
heat pump and the heat recovery systems.
Fig. 21 —Connecting the Communication Cable (Indoor Unit to Outdoor Unit) Using the Supplied Connector
LEGEND
ACB — Auxiliary Control Board
P Q
P Q
P Q
To outdoor / indoor/
MDC unit comm.bus
To wired controller comm. bus
XT2
CAUTION
Failure to follow these procedures may result in personal
injury or damage to equipment.
NEVER CONNECT the main power source to the control
or communication terminal block.
USE AN APPROPRIATE SCREWDRIVER for
tightening the terminal screws. Do not over tighten the
terminal screws.
IMPORTANT: Wiring for communication shall be two
inches or more apart from power source wiring to avoid
electric noise. Do not insert control/communication and
power source wire in the same conduit.
Pay attention to polarity of the communication wire.
Connector in accessory kitConnector on indoor unit Communication cable
in field
Fig. 17 —Shearing Outdoor Connector