Outdoor Air Enthalpy Control; Differential Enthalpy Control; Return Air Enthalpy Sensor; Smoke Detectors - Carrier 50HCQ Installation Instructions Manual

Outdoor Air Enthalpy Control

(P/N 33CSENTHSW)
The enthalpy control (33CSENTHSW) is available as a
field−installed accessory to be used with the EconoMi$er2
damper system. The outdoor air enthalpy sensor is part of
the enthalpy control. (The separate field−installed
accessory return air enthalpy sensor (33CSENTSEN) is
required for differential enthalpy control. See Fig. 66.)
Locate the enthalpy control in the economizer next to the
Actuator Motor. Locate two GRA leads in the factory
harness and connect the gray lead labeled "ESL" to the
terminal labeled "LOW". See Fig. 66. Connect the enthalpy
control power input terminals to economizer actuator power
leads RED (connect to 24V) and BLK (connect to GND).
Enthalpy
Switch
24V RED
GND BLK
LOW GRA
Factory Wiring Harness
Fig. 66 − Enthalpy Switch (33CSENTHSW) Connections
The outdoor enthalpy changeover setpoint is set at the
enthalpy controller.
Differential Enthalpy Control —
Differential enthalpy control is provided by sensing and
comparing the outside air and return air enthalpy
conditions. Install the outdoor air enthalpy control as
described above. Add and install a return air enthalpy
sensor.
Return Air Enthalpy Sensor —
Mount the return−air enthalpy sensor (33CSENTSEN) in
the return−air section of the economizer. The return air
sensor is wired to
(33CSENTHSW). See Fig. 67.
24V
– 4-20
Main
GND
+ VDC
Out
LOW
Outside Air
Enthalpy Switch
+ 24-36
VDC In
– 4-20 Main
Out
Fig. 67 − Outside and Return Air Enthalpy Sensor
Wiring
PL6-1 (24-V)
PL6-4 (COM)
7 CTB ECON
(P'LINK: to J4-2) or
(RTU Open: to J2-6)
C11160
the enthalpy controller
RED PL6-1 (24-V)
BLK PL6-4 (COM)
CTB ECON
GRA 7
(P'LINK: to J4-2) or
(RTU Open: to J2-6)
Return Air
Enthalpy
Sensor
C11161

Smoke Detectors

Smoke detectors are available as factory−installed options on
50HCQ models. Smoke detectors may be specified for
Supply Air only or for Return Air without or with
economizer or in combination of Supply Air and Return Air.
All components necessary for operation are factory−provided
and mounted. The unit is factory−configured for immediate
smoke detector shutdown operation; additional wiring or
modifications to unit terminal board may be necessary to
complete the unit and smoke detector configuration to meet
project requirements.
Units equipped with factory−optional Return Air smoke
detectors require a relocation of the sensor module at unit
installation. See Fig. 68 for the as shipped location.
Return Air
Smoke Detector
(as shipped)
Fig. 68 − Return Air Smoke Detector, Shipping Position
Completing Installation of Return Air Smoke Sensor:
1. Unscrew the two screws holding the Return Air
Smoke Detector assembly. See Fig. 69, Step 1. Save
the screws.
2. Turn the assembly 90 degrees and then rotate end to
end. Make sure that the elbow fitting is pointing
down. See Fig. 69, Step 2.
3. Screw the sensor and detector plate into its operating
position using screws from Step 1. See Fig. 69, Step 3.
4. Connect the flexible tube on the sampling inlet to the
sampling tube on the basepan.
Additional Application Data —
Refer to the Application Data sheet titled Factory
Installed Smoke Detectors for Small and Medium Rooftop
Units 2 to 25 Tons for discussions on additional control
features of these smoke detectors including multiple unit
coordination.
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