Bryant 547K 04-07 Series Service And Maintenance Instructions page 36

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 (P/N: 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$er IV can be used for free cooling. The sensor has
8 selectable temperature changeover setpoints, ranging from
48°F to 78°F. The temperature changeover is set using the
3 DIP switches on the sensor. See Fig. 59.
Fig. 59 — C7660 Temperature Sensor
Supply Air Temperature (SAT) Sensor
The supply air temperature sensor is a field-installed 3 K
thermistor located on the fan deck. See Fig. 60. This sensor is
factory installed. The operating range of temperature
Table 11 — EconoMi$er IV Input/Output Logic
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
Compressor
Stage 2 Occupied
On
Off Minimum position
Off
Off Modulating
(between minimum position
Off
and full-open)
Off Minimum position
On
Modulating
Off (between minimum position
and DCV maximum)
Off
Off
Off Modulating
Off
measurement is 0°F to 158°F (–18°C to 70°C). See Table 12 on
page 37 for sensor temperature/resistance values.
Supply Air
Temperature
Sensor
Fig. 60 — 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.
Outdoor Air Lockout Sensor
The EconoMi$er IV is equipped with an ambient temperature
lockout switch located in the outdoor airstream which is used
to lock out the compressors below a 42°F (6°C) ambient tem-
perature. See Fig. 54 on page 33.
36
OUTPUTS
N Terminal b
Unoccupied
c
Modulating
closed and full-open)
d
Modulating
closed and DCV maximum)
Modulating
e
Closed
c (between
Closed
(between
d
f