Carrier 48FC 08-16 Series Service And Maintenance Instructions page 51

INPUTS
Demand Enthalpy
Controlled
Ventilation
Outdoor
(DCV)
High
(Free Cooling
LED Off)
Below Set
(DCV LED
Off)
Low
(Free Cooling
LED On)
High
(Free Cooling
LED Off)
Above Set
(DCV LED
On)
Low
(Free Cooling
LED On)
NOTE(S):
a. For single enthalpy control, the module compares outdoor enthalpy to the ABCD set point.
b. Power at N terminal determines Occupied/Unoccupied setting: 24 vac (Occupied), no power (Unoccupied).
c. Modulation is based on the supply-air sensor signal.
d. Modulation is based on the DCV signal.
e. Modulation is based on the greater of DCV and supply-air sensor signals, between minimum position and either maximum position (DCV) or fully open (supply-air signal).
f. Modulation is based on the greater of DCV and supply-air sensor signals, between closed and either maximum position (DCV) or fully open (supply-air signal).
Outdoor Air Temperature (OAT) Sensor
The outdoor air temperature sensor (HH57AC074) is a 10 to
20 mA device used to measure the outdoor-air temperature.
The outdoor-air temperature is used to determine when the
EconoMi$er IV can be used for free cooling. The sensor has 8
selectable temperature changeover setpoints, ranging from
48°F to 78°F. The temperature changeover is set using
the 3 dip switches on the sensor See Fig. 72.
Fig. 72 — C7660 Temperature Sensor
Table 13 — EconoMi$er IV Input/Output Logic
Compressor
a
Y1 Y2
Return Stage 1
On On On
Low On Off On
Off Off Off
On On On
High On Off Off
Off Off Off
On On On
Low On Off On
Off Off Off
On On On
High On Off Off
Off Off Off
OUTPUTS
Stage 2 Occupied
On
Off Minimum position
Off
Off
Modulating
c
min. position and full-open)
Off
Off Minimum position
On
Modulating (between min.
d
Off
position and DCV maximum)
Off
Off
Off Modulating
Off
Supply Air Temperature (SAT) Sensor
The supply air temperature sensor is a field-installed 3 K
thermistor located on the fan deck. See Fig. 73. The operating
range of temperature measurement is 0°F to 158°F (–18°C to
70°C). See Table 14 for sensor temperature/resistance values.
Supply Air
Temperature
(SAT) Sensor
Fig. 73 — Supply Air Sensor Location
The temperature sensor looks like an eyelet terminal with wires
running to it. The sensor is located in the "crimp end" and is
sealed from moisture.
51
N Terminal
b
Unoccupied
Closed
(between Modulating
c
closed and full-open)
Closed
Modulating
d
closed and DCV maximum)
e Modulating
(between
(between
f