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The Ductless Split System of Choice
5
As of 12/01/04, the 24V control transformer is located in
the air handler unit.
This provides low volt control power
to both the air handler and condenser. Depending on the
models selected, the
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/WHP)
or terminals (CCP/CHP/FCP/FHP) 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.
HEAT PUMP CONNECTION - UNIT MOUNT
CONTROLS Two-Stage Heating
When connecting to a defrosting heat pump, such as
EMI model SHC, indoor units with electric heat utilize five
interconnecting
low Volt
wires between the indoor and
outdoor units. When connecting to limited range heat pumps
such as EMI models MH2 and MH4
built after 12/01/04
,
indoor units with electric heat utilize four interconnecting
low Volt wires. In this case the “R” (red) may not be needed
and should be protected by a wire nut from making contact
with the junction box or other metal surfaces.
LOW VOLT INTERCONNECT WIRING FOR UNIT MOUNTED CONTROLS
In addition to the “Y” and “C” connections required for
cooling, heat pumps require a reversing valve control wire
“O” (orange) that is energized in the cooling mode. If the
indoor unit has an electric heater then a ”W” (white) wire
connection may also be needed to energize the indoor
electric heat. Heat pumps models SHC require an “R”
connection between the indoor and outdoor unit to provide
power to the defrost control board in the condenser.
Heat pump models MH2 and MH4 do not require an “R”
connection
after 12/01/04
since the transformer is located
in the air handler.
Note:
Two-stage heating requires the combination of a
heat pump condenser and an indoor unit that is equipped
with an electric strip heater. The indoor electric heater
will energize as the second stage heat source, when the
room temperature falls by two degrees or more below the
set point, and also during the defrost mode for models
SHC. For limited range heat pumps models MH2 and
MH4, heat pump operation will cease when the outdoor
temperature falls below 35°F. In this case the electric
strip heater will remain sole heat source.
Refer to low Volt interconnect diagram interconnect diagram
Figure 1
for unit mounted controls.
REMOTE THERMOSTAT CONTROLS
As of 12/01/04, the 24V control transformer is located in
the air handler unit.
This provides low volt control power
to both the air handler and condenser. Depending on the
models selected, the interconnect control wiring may be
effected.
Note: All
low Volt
interconnect wiring must be at
least 18 awg.
Choosing a Remote Wall Mounted Thermostat:
See
“Wall Thermostat Control” section Pg. 21-22
Figure 1
COMMON TO ALL AIR HANDLERS
Continued
