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—15—
VIII. STEP 8 — MAKE CONNECTIONS BETWEEN INDOOR
AND OUTDOOR UNITS
The thermostat is wired between the indoor and outdoor
units to make the system complete.
A. Check AccuRater Metering Device
The correct AccuRater (bypass type) refrigerant control is
required for system capacity optimization. An AccuRater
device (see Fig. 19) is supplied with the outdoor unit. Refer to
Tables 4A-4C to determine the correct AccuRater piston size
and charge combination required for the condenser/evaporator
system being installed.
Piston style as shown in Fig. 19 is shipped with the unit. Do
not interchange components between the AccuRater device
types.
B. Cooling Only Systems
The following connections must be made to the outdoor unit
for it to operate as a system with the indoor unit:
Route 2 wires of field-supplied 18-gage AWG (American Wire
Gage) thermostat cable between the low-voltage terminal
block of the fan coil unit and the blue and brown low-voltage
wires in the outdoor unit low voltage terminal block. Connect
the wires Y1 to Y and C to C. See Fig. 20.
C. Heat Pump Systems
The following connections must be made to the outdoor unit
for it to operate as a system with the indoor unit:
Route 5 wires of field-supplied 18-gage AWG thermostat
cable between the low-voltage terminal block of the fan coil
and the outdoor unit low-voltage terminal block. Connect Y1
to Y, R to R, O to O, W2 to W2, and C to C with the wires. See
Fig. 21.
The heat pump unit uses a timed defrost method. The timed
defrost can be field set for 30, 50, or 90 minutes. The timed
defrost is factory set for 90 minutes.
538A018-060
538B018-060
Fig. 19 — AccuRater (Bypass Type)
Metering Device Components
a38-6777
a38-6758