Carrier 40VMM007A 3 Series Installation And Maintenance Instructions Manual

17Step 6 — Position and Connect Controller —Wired controllers should be installed in a position thatmaintains good temperature control:• Position the thermostat approximately 48 inches abovefloor level.• Do not position the thermostat where it can be directlyaffected by the unit’s discharge airstream.• Avoid external walls and drafts from windows and doors.• Avoid positioning near shelves and curtains as theserestrict air movement.• Avoid heat sources such as direct sunlight, heaters,dimmer switches, and other electrical devices.• See Fig. 24 for an example of communication wireconnection.CONTROL WIRING1. The communication wire should be 2-core strandedshielded cable.2. For indoor unit 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.Fig. 24 —Communication Wire ConnectionOPTION/EXTENSIONS OF COMMUNICATIONWIRING — To extend control wiring or to make terminalconnections, use the PQE connection wire supplied in theaccessory kit and follow the steps below.1. Cut the connector on the outdoor unit side as shown inFig. 25 below.2. Strip a suitable length of the insulation layer as shown inFig. 26 below.Fig. 26 —Stripping The Wire3. Use a suitable screwdriver to fix the communication wireon the outdoor unit communication terminal as shown inFig. 27 below.If communication wires are used to connect indoor units, findthe corresponding port and plug it in as shown in Fig. 28.Fig. 28 —Connecting the Communication WiresIf it is not possible to buy communication wires from Carrier,connect the indoor unit side of communication wires using theconnector provided with the accessories as shown in Fig. 29below. See Fig. 30 and 31 for typical communication wiring ofthe heat pump and the heat recovery systems.LEGENDACB — Auxiliary Control BoardTo outdoor/indoor/MDC unitscomm. bus To wired controller comm. busXT2Fig. 25 — Shearing Outdoor ConnectorCAUTIONFailure to follow these procedures may result in personalinjury or damage to equipment.NEVER CONNECT the main power source to the controlor communication terminal block.USE AN APPROPRIATE SCREWDRIVER fortightening the terminal screws. Do not over tighten theterminal screws.IMPORTANT: Wiring for communication shall be twoinches or more apart from power source wiring to avoidelectric noise. Do not insert control/communication andpower source wire in the same conduit.Pay attention to polarity of the communication wire.Fig. 27 — Connecting Communication Wire toOutdoor Unit Communication Terminal