Carrier 48TC*D08 - Economizer controls; Outdoor Air Enthalpy Control; Differential Enthalpy Control

41
Configure the unit for Thermostat Mode — Connec t to the
CCN bus using a CCN service tool a nd navigate to
PremierLink Configuration screen for Operating Mode.
Default setting is Sensor Mode (value 1). Change the
value to 0 to reconfigure the controller for Thermostat
Mode.
When the PremierLink is configured for Thermostat
Mode, these functions are not available: Fire Shutdown
(FSD), Remote Occupied (RMTOCC), Compressor Safety
(CMPSAFE), Supply Fan Status (SFS), and Filter Pressure
Switch (FILTER).
Economizer controls —
Outdoor Air Entha lpy Control (PNO HH57AC077) --
The enthalpy control (HH57AC077) is availa ble as a
field--installed accessory to be used with the EconoMi$er2
dampe r system. The outdoor air enthalpy sensor is part of
the enthalpy control. (The separate field--installed
accessory return air entha lpy sensor (HH57AC078) is
required for differential enthalpy control. See Fig. 50.)
Loca te the enthal py control in the ec onomizer hood.
Locate two GRA leads in the factory harness and connect
these leads to ent halpy control sensors 2 and 3. See Fig.
49. Connect the enthalpy control power input terminals to
economizer actuator power leads RED (connect to TR)
and BLK (conne ct to TR1).
6
7
LCTB
ECON
3
2
Enthalpy
Switch
GRA
GRA
Factory Wiring Harness
C08218
Fig. 49 -- Enthalpy Switch (HH57AC077) Connections
The outdoor enthalpy changeover setpoint is set at the
enthalpy controller.
The enthalpy control receives the outdoor air enthalpy
from the outdoor air enthalpy sensor a nd provides a dry
contact switch input to the PremierLink controller. A
closed contact indicates that outside air is preferred to the
return air. An open contact indicates that the economizer
should remain at minimum position.
Differential Enthalpy Control — Differential enthalpy
control is provided by sensing and comparing the outside
air and return air enthal py conditions. Install the outdoor
air enthalpy control as described above. Add and install a
return air enthalpy sensor.
Return Air Ent halpy Sensor — Mount the return--air
entha lpy sensor (HH57AC078) in the return--air duct. The
return air sensor is wired to the enthalpy controller
(HH57AC077). See Fig. 50.
LED
A
B
C
D
TR TR1
SO
SR
2
3
1
+
+
BRN
RED
GRAY/ORN
GRAY/RED
WIRE HARNESS
IN UNIT
BLK
RED
S
+
(RETURN AIR
ENTHALPY
SENSOR)
S
+
(OUTDOOR
AIR
ENTHALPY
SENSOR)
ENTHALPY CONTROLLER
NOTES:
1. Remove factory-installed jumper across SR and + before connecting
wires from return air sensor.
2. Switches shown in high outdoor air enthalpy state. Terminals 2 and 3
close on low outdoor air enthalpy relative to indoor air enthalpy.
3. Remove sensor mounted on back of control and locate in outside air-
stream.
C06019
Fig. 50 -- Outside and Return Air Enthalpy Sensor
Wiring
To wire the return air enthalpy sensor, perform the
following:
1. Use a 2--conductor, 18 or 20 AWG, twisted pair cable
to connect the return air enthalpy sensor to the
enthalpy controller.
2. At the enthalpy control remove the factory--installed
resistor from the (SR) and (+) termina ls.
3. Connect the field--supplied RED wire to (+) spade
connec tor on the return air e nthalpy sensor and the
(SR+) terminal on the enthalpy controller. Connect
the BLK wire to (S) spade connector on the ret urn air
entha lpy sensor and the (SR) terminal on the enthalpy
controller.
NOTE: The enthalpy control must be set to the “D”
setting for differential enthalpy c ontrol to work properly.
The enthalpy c ontrol receives the indoor and return
enthalpy from the outdoor and return air entha lpy sensors
and provides a dry contact switch input to the
PremierLink controller. A closed contact indicates that
outside air is preferre d to the return air. An open contac t
indicates that the economi zer should remain at minimum
position.
Indoor Air Quality (CO
2
sensor) — The indoor air quality
sensor accessory monitors space carbon dioxide (CO
2
)
levels. This information is used to monitor IAQ levels.
Several types of sensors are available, for wall mounting
in the spac e or in return duct, with and without LCD
display, and in combination with space temperature
sensors. Sensors use infrared technol ogy to measure the
levels of CO
2
present in the space air.
48TC