Step 6 - Position And Connect Controller - Carrier 40VMI Series Installation And Maintenance Instructions Manual

Step 6 — Position and Connect Controller —
Wired controllers should be installed in a position that
maintains good temperature control:
• Position the thermostat approximately 48 inches 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. 28 for an example of communication wire
connection.
CONTROL WIRING
1. The communication wire should be 2-core stranded
shielded cable.
2. For IDU (indoor unit) and ODU (outdoor unit)
communication, use P, Q terminals. Shielded core should
be used for ground.
3. Wiring should be done according to the wiring diagram.
4. Communication wire must not form a closed loop.
HA HB
To wired
controller
comm. bus
Fig. 28 —Communication Wire Connection
OPTION/EXTENSIONS OF COMMUNICATION
WIRING — To extend control wiring or make terminal
connections, use the PQE connection wire supplied in the
accessory kit and follow the steps below.
1. Cut connector on outdoor unit side (Fig. 29).
Fig. 29 —Shearing Outdoor Connector
2. Strip a suitable length of insulation layer (Fig. 30).
Fig. 30 — Stripping the Wire
P Q
To outdoor/
indoor/MDC
units comm. bus
3. Use a suitable screwdriver to fix the communication wire
on the outdoor unit communication terminal (Fig. 31).
Fig. 31 —Connecting Communication Wire to
Outdoor Unit Communication Terminal
If communication wires are use to connect indoor units, find the
corresponding port and plug it directly (Fig. 32).
Fig. 32 —Connecting the Communication Wires
See Fig. 33 and 34 for typical communication wiring of the heat
pump and heat recovery systems.
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: Communication wiring shall be 2 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.
14
CAUTION