
FRONT VIEW
SIDE VIEW
MOUNTING PLATE
48/50A, 48/50N,
48/50P, 48/50Z
CO2 Sensor Accessory
Installation Start-Up and Service Instructions
Part No. CRCBDIOX002A00
CONTENTS
Page
SAFETY CONSIDERATIONS . . . . . . . . . . . . . . . . . . . . 1
GENERAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Check Package Contents . . . . . . . . . . . . . . . . . . . . . . 2
INSTALLATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
48/50A Units . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
48/50P and 48/50Z Units . . . . . . . . . . . . . . . . . . . . . . . 2
48/50N Units . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
START-UP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Configuring the ComfortLink Controller . . . . . . . . . . 5
Sensor Self-Calibration . . . . . . . . . . . . . . . . . . . . . . . . 5
SERVICE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Cleaning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
TROUBLESHOOTING . . . . . . . . . . . . . . . . . . . . . . . . . 5
SAFETY CONSIDERATIONS
Installation of this accessory can be hazardous due to system
pressures, electrical components, and equipment location (such
as a roof or elevated structure). Only trained, qualified installers and service technicians should install, start-up, and service
this equipment.
When installing this accessory, observe precautions in the literature, labels attached to the equipment, and any other safety
precautions that apply:
• Follow all safety codes
• Wear safety glasses and work gloves
• Use care in handling and installing this accessory
It is important to recognize safety information. This is the safetyalert symbol . When you see this symbol on the unit and in
instructions or manuals, be alert to the potential for personal
injury.
Understand the signal words DANGER, WARNING, CAUTION,
and NOTE. These words are used with the safety-alert symbol.
DANGER identifies the most serious hazards which will result in
severe personal injury or death. WARNING signifies hazards
which could result in personal injury or death. CAUTION is used
to identify unsafe practices, which may result in minor personal
injury or product and property damage. NOTE is used to highlight
suggestions which will result in enhanced installation, reliability,
or operation.
WARNING
Prior to installation of this accessory, make sure all power is
disconnected to the unit and locked out. Failure to disconnect
power supply prior to servicing may result in serious injury.
GENERAL
The CO2 sensor (Fig. 1) is designed to monitor carbon dioxide
(CO
) levels in the return air and interface with the Com-
2
fortLink controller on the rooftop air-conditioning unit. The
sensor perceives CO
(ppm) range and provides outputs indicating this level. The
unit utilizes a 4 to 20-mA analog signal. The ComfortLink controller uses this signal to control the economizer damper position and ensure adequate level of outside air in the building.
This is one of several approved methods of controlling the indoor-air quality (IAQ) in a building and meets the requirements
of local building codes and ASHRAE (American Society of
Heating, Refrigerating and Air-Conditioning Engineers) Standard 62. The control sensor features a membrane-covered
waveguide and sample chamber that produces stable, reliable,
and highly accurate carbon dioxide readings. See Table 1 for
sensor usage.
The sensor is self-calibrating and should not need to be manually calibrated.
48/50A 020-060
48/50N2,N3,N4,N5,N6,N7,N8,N9 75-150 tons
48/50P 030-100
48/50ZG,ZN 030-105
50Z2,Z3 030-105
48/50ZT,ZW,Z6,Z8 075-105
50ZX,ZZ,Z7,Z9 075-105
levels in the 0 to 2,000 parts per million
2
Fig. 1 — CO
Table 1 — Sensor Usage
UNIT SIZE
Sensor
2
Catalog No. 04-53480236-01 Printed in U.S.A. Form 48/50-90SI Pg 1 3-19 Replaces: 48/50-81SI
Manufacturer reserves the right to discontinue, or change at any time, specifications or designs without notice and without incurring obligations.

Check Package Contents
Remove accessory packaging and inspect shipment for damage. If any damage is found, file a claim with the shipping
agent immediately. If any item is missing or any part does not
assemble properly, notify your Carrier distributor. Table 2 lists
the accessory package contents.
6. Remove the blankout plate from the partition, just above
the auxiliary control box.
7. Attach the sensor to the mounting plate.
8. Mount the bracket to the partition using 2 sheet metal
screws (see view F in Fig. 2).
9. Connect the electrical harness (PL18).
Table 2 — Accessory Package Contents
ITEM QUANTITY
Sensor (Part No. HH99ZZ019) 1
CO
2
Bracket (48/50A) 1
No. 8-18 x
1
/4 AB-14 x 5/8 Screw 2
Electrical Harness* 1
Bracket (48/50N,48/50P,48/50Z) 1
*Do not use the electrical harness provided in this kit for 48/50N, 48/
50P and 48/50Z units.
1
/4 Screw 2
INSTALLATION
48/50A Units
The CO2 sensor is to be installed in the predrilled holes located
above the auxiliary control box (see Fig. 2).
1. Shut off unit power supply.
2. Open the hinged auxiliary control box access door and
secure.
3. Remove the sensor and cover from the sensor mounting
plate.
4. Secure mounting plate to bracket (48/50A) with no. 8
screws (see Fig. 3).
5. Wire the electrical harness to the sensor as shown in
Fig. 3 and 4.
48/50P and 48/50Z Units
The CO2 sensor is to be installed in the predrilled holes located
in the power exhaust section. See Fig. 5-11.
1. Shut off unit power supply.
2. Open the power exhaust section doors/panels to gain
access.
3. Remove the sensor and cover from the sensor mounting
plate.
4. Secure mounting plate to the bracket with no. 8 screws.
5. The electrical wire harness for the CO
installed. Locate the four wires in the power exhaust
section. Wire the electrical harness to the sensor as
shown in Fig. 4.
6. Attach the sensor to the mounting plate.
7. Mount the bracket to the appropriate location:
• Size 030-050 units with power exhaust, see Fig. 5 and 6.
• Size 030-050 units with economizer only, see Fig. 7.
• Size 030-050 units with no economizer or power ex-
haust, see Fig. 8.
• 48/50P055-100 and 48/50Z055-105 units with power ex-
haust, see Fig. 9.
• 48/50P055-100 and 48/50Z055-105 units with econo-
mizer only, see Fig. 10.
• 48/50P055-100 and 48/50Z055-105 units with no econo-
mizer or power exhaust, see Fig. 11.
8. Restore power to unit.
sensor is factory
2
2

CO
2
SENSOR
AUXILIARY
CONTROL BOX
PARTITION
BRACKET
(48/50A)
ELECTRICAL
HARNESS
VIEW F
PL18
(48/50A
ONLY)
BRACKET
(48/50A)
SENSOR MOUNTING PLATE
HOLES MUST LINE-UP
COVER SCREW
SENSOR COVER
Fig. 2 — 48/50A CO
Sensor Mounting Location
2
Fig. 4 — Harness Wiring Connections
Fig. 3 — CO
Sensor Assembly
2
3