Low Volt Interconnect - A & T International 1 Service Manual

LOW VOLT INTERCONNECT WIRING FOR UNIT MOUNTED CONTROLS
24V control transformer is located in air handler unit. This
provides low volt control power to air handler . Depending on
models selected, low Volt interconnect control wiring may be
effected.
Note: All low volt interconnect wiring must be at
least 18 awg.
COOLING ONLY UNITS With or Without Heat
Cooling only units utilize two low Volt interconnecting wires
between the indoor and outdoor units. Wires (WCP) or terminals
(CCP) designated "Y" (yellow) and "C" (brown) of the air handler
should be connected to the corresponding "Y" (yellow) and "C"
(brown) wires or terminals of the condenser. Other wires or
terminals such as "R" (red) or "O" (orange) may not be needed
and should be protected by a wire nut from making contact with
the junction box or other metal surfaces.
Refer to low Volt interconnect diagram interconnect diagram
Figure 1 for unit mounted controls.
Figure 1A
Figure 1
Remote Thermostat Controls
24V control transformer is located in air handler unit. This
provides low volt control power to air handler. Depending on
models selected, interconnect control wiring may be effected.
All low Volt interconnect wiring must be at least 18
awg.
Choosing Remote High-Wall Thermostat: See "Wall
Thermostat Control" section Pg. 15-16
COOLING ONLY UNITS With or Without Heat
Depending on the thermostat required or selected, cooling only
air handles may utilize four to six low Volt interconnecting wires
between the indoor unit and thermostat. Some thermostats do
not require the use of the "C" (brown) connection. In this case,
ensure that any unused wires are insulated with a wire nut to
prevent them from making contact with the junction box or other
metal surfaces.
If the indoor unit has electric heat or hydronic heat then a "W"
connection is required between the thermostat and indoor unit.
Refer to low Volt interconnect diagram interconnect diagram
Figure 2 for remote wall thermostat controls
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