Sensor Adjustment; Pressure Sensors - Carrier 33CS Installation, Service And Instructions

WIRE SENSORS TO DAMPER BOARD — The damper
board sensor wiring bundle contains the wires required to
connect the sensors. The duct temperature sensor and wiring
is part of the damper actuator. No wiring is required.
NOTE: For IAQ and pressure sensor wiring and installation,
see sections below.
INDOOR-AIR QUALITY SENSOR INSTALLATION — An
indoor-air quality sensor is designed for use with the Carrier
Comfort system. The sensor has a range of 0 to 5000 ppm
of CO . The factory setting is 1000 ppm. This set point is
2
adjustable only through software. An isolated power supply
of 16 to 24 vac is required and supplied with the sensor, with
a 300 mA average and a 500 mA peak. The IAQ sensors are
available in 3 models: Wall Mount with LED (light-emitting
diode), Wall Mount, and Duct Mount.
The duct-mounted sensor is mounted in the duct (typi-
cally the return air duct). It reads the level of CO
cation. The sensor is shipped mounted in an aspirator box
for mounting to the ductwork. A 1
the sensor sampling tube. This is a typical VVT system
application.
When the IAQ sensor is used in Monitor-Only applica-
tions, it is usually duct-mounted and wired to a zone con-
troller relay pack (local IAQ). When the IAQ sensor is used
in VVT Monitor applications, it is usually duct-mounted and
wired to the bypass damper (system IAQ).
To wire the IAQ sensor, perform the following:
1. Wire the dry contact relay output from the sensor (con-
nections 3 and 4) to the red and black wires of the "O"
section of the PS sensor harness of the bypass controller
damper. The PS sensor harness is supplied with a pres-
sure sensor for use with the bypass damper. Recom-
mended gage of wire is 14, stranded. See Fig. 3.
2. Wire the 2 wires from the isolated 24 vac power supply
to the power input side of the sensor (connections 1
and 5). Recommended gage of wire is 14, stranded. The
green/red LED on the sensor shows steady green during
normal operation.
Configure the options associated with the sensor. Refer to
the Indoor-Air Quality Sensor section on page 12.
PRESSURE SENSOR INSTALLATION — The 33CS pres-
sure sensor must be interfaced to the bypass controller mas-
ter bypass damper using the factory supplied 8 wire harness.
Three wires are for the pressure sensor and the 2 wires marked
"O" are for an optional IAQ sensor. See Fig. 3. Refer to the
pressure sensor installation instruction for more informa-
tion. See Fig. 4.
CONNECT POWER TO DAMPER ACTUATOR — After
the wiring has been completed, provide power to the damper
actuator by connecting the power wiring bundle to a 24 vac
transformer. Power required to the damper actuator is 24 vac/
30 va. Typical wiring is 18 gage thermostat wire (standard
or plenum cable). The maximum load of a relay contact is
24 vac, 1 amp. A short in the field wiring will cause non-
warranty damage to the bypass controller. Test before at-
taching to bypass controller. Once power has been provided,
the damper actuator will provide power to the bypass con-
troller. The bypass controller display will appear on the screen.
If the display is blank or blinking, recheck the wiring con-
nections between the bypass controller and damper actuator.
at its lo-
2
1 ⁄ -in. hole is required for
2

Sensor Adjustment

tem external static pressure, the bypass controller must be
interfaced to a 33CS pressure sensor. The pressure sensor
measures actual system static pressure.

Pressure Sensors

sensors available. Depending on the static pressure the sys-
tem will operate at, choose the correct pressure sensor. The
33CSPS-01 has an operating range from 0.05 to 0.5 in. wg.
The 33CSPS-02 has an operating range from 0.2 to
2.0 in. wg.
The pressure sensor measures the system static pressure
through one or multiple PSP (static pressure pickups) that
are mounted downstream of the bypass damper in the sys-
tem duct. When the system duct layout makes it impossible
to locate the PSP in an area of laminar flow, multiple PSPs
may be installed and then connected to calculate an average
system pressure. See Fig. 5.
When calibrated, the pressure sensor is highly accurate
and capable of measuring static pressure with a resolution of
0.01 in. wg. The bypass controller displays the system static
pressure in inches wg.
EQUIPMENT SET UP FOR PRESSURE SENSOR CALI-
BRATION — The following equipment is needed for pres-
sure sensor calibration:
• accurate manometer or Magnehelic pressure gage
• 1/4 in. (OD) tee fitting with 3 ports
• 1 ft length of 1/4 in. (ID) flexible tubing to run from the
pressure sensor to one port of the tee fitting
• sufficient length of 1/4 in. (ID) flexible tubing to run from
one of the tee fitting ports (located near pressure sensor)
to the manometer or Magnehelic (located near the bypass
controller).
For the manometer or Magnehelic gage to measure the
correct pressure, a 1/4 (OD) tee fitting must be temporarily
installed as a pressure tap in the flexible tubing running be-
tween the pressure sensor and the PSP pressure pickup.
NOTE: The pressure sensor and PSP pressure pickup must
be installed according to the installation instructions pack-
aged with each component.
Perform the following procedure to set up the pressure
sensor and manometer or Magnehelic gage:
1. Locate the manometer or Magnehelic gage so the static
pressure readings can be easily viewed from the bypass
controller location.
2. At the pressure sensor, remove the flexible tube con-
nected to the high-pressure port.
3. Install one port of the tee fitting into the end of the flex-
ible tube that was disconnected from the pressure sensor
in step 2.
4. Using 1 ft length of flexible tubing, connect the second
port of the tee fitting to the pressure sensor high-pressure
port.
5. Using the remaining length of flexible tubing, connect the
third port of the tee fitting to the high-pressure inlet of
the manometer or Magnehelic gage.
NOTE: The low-pressure port on both the pressure sensor
and manometer or Magnehelic gage must be open to the
atmosphere.
3
— To regulate the Carrier VVT sys-
— There are two different pressure