Carrier 35L Series, Installation And Start-Up Instructions Manual

Page: 7 / 20

7
Carrier inlet areas are shown in Table 6. The design air
volume is shown in this table. It can be determined from this
table that the average design air velocity for those units is equal
to 2656 fpm at 1.0-in. wg.
Table 6 — Inlet Areas
.
*35L units only.
NOTE: For Carrier ComfortID™ terminals, all flow sizes are normal-
ized using a single Probe Multiplier (PMF) for all sizes equal to
2.273.
PNEUMATIC CONTROLS
All control packages are pressure independent and include
standard linear airflow sensors in both the hot and cold inlets
for variable air volume control (control sequence 1500 to 1507)
or an airflow sensor in one inlet and unit discharge for constant
volume control arrangements (control sequence 1508 to 1523).
Preparation for Balancing
1. Inspect all pneumatic connections to assure tight fit and
proper location.
2. Verify that the thermostat being used is compatible with
the control sequence provided (direct acting or reverse
acting).
3. Check main air pressure at the controller(s). The main air
pressure must be between 15 psi and 25 psi. (If dual or
switched-main air pressure is used, check the pressure at
both high and low settings.) The difference between
“high” pressure main and “low” pressure main should be
at least 4 psi, unless otherwise noted, and the “low” set-
ting difference should exceed 15 psi.
4. Check that the unit damper will fail to the proper position
when main air pressure is lost. Disconnect the pneumatic
actuator line from the velocity controller and observe the
VAV damper position. The damper should fail to either a
normally open position (indicator mark on shaft end is
horizontal) or a normally closed position (indicator mark
on shaft end is vertical).
5. Check that there is primary airflow in the inlet duct.
6. Connect a Magnehelic gage, inclined manometer or other
differential pressure measuring device to the balancing
taps provided in the velocity probe sensor lines. The
manometer should have a full scale reading of 0.0 to
1.0 in. wg. The high pressure signal is delivered from the
front sensor tap (away from the valve), and the low pres-
sure signal is delivered from the back line (near the
valve). The pressure differential between high and low
represents the amplified velocity pressure in the inlet
duct.
7. Read the differential pressure and enter the Flow Probe
Chart to determine the airflow in the terminal unit. This
chart is shown in Fig. 4A-4C and is also attached to the
side of each unit. For example, a differential pressure of
0.10 in. wg for a size 8 unit yields an airflow of 275 cfm.
Volume controller for units is shown in Fig. 5.
Balancing Procedure (Control Sequences
1500-1523)
1. Damper action is factory set at NO (normally open), or
NC (normally closed). To reselect loosen damper selec-
tion switch screw and align pointer with damper pointer
and tighten screw. The spring range of the actuator is not
critical since the controller will output the necessary pres-
sure to the actuator to position the damper according to
set point. (See Fig. 5.)
2. Pipe the controller: Connect port “B” to the damper actu-
ator. Connect port “M” to the clean, dry main air. Connect
port “T” to the thermostat output. Connect port “H” to the
total pressure tap on the airflow sensor. Connect port “L”
to the static pressure tap on the airflow sensor.
The controller can be set up for cooling or heating applications
using either a direct acting (DA) or reverse acting (RA) ther-
mostat signal. The two flow adjustments are labeled “LO
STAT
∆
P” and “HI STAT
∆
P.”
35L,N UNIT SIZE 04* 05* 06 07* 08 09*
INLET
DIAMETER
4.0 5.0 6.0 7.0 8.0 9.0
CFM AT 1 IN. WG 232 362 502 710 927 1174
INLET AREA
(sq ft)
0.087 0.136 0.196 0.267 0.349 0.442
35L,N UNIT SIZE 10 12 14 16 22*
INLET DIAMETER 10.0 12.0 14.0 16.0 16 x 24
CFM AT 1 IN. WG 1449 2086 2840 3709 7250
INLET AREA
(sq ft)
0.545 0.785 1.069 1.396 2.640
10000
8000
6000
4000
2000
1000
800
600
400
200
100
80
60
40
20
10
0.01 .03 .05 0.1 0.3 0.5 1
710
522
362
232
2086
1449
1174
927
3709
2840
7250
FLOW PROBE PRESSURE DIFFERENTIAL IN. WG
CFM
CFM
A
T
ONE
INCH
SIGNAL
SIZE
4
SIZE
5
SIZE
6
SIZE
7
SIZE
8
SIZE
9
SIZE
10
SIZE
12
SIZE
14
SIZE
16
SIZE
22
NOTE: Size 22 available on 35L units only.
Fig. 4C — Dual Duct Inlet Flow Probe Chart
(35L only)
T
H
L
B
M
NO
NC
G
RESET START
LO STAT ∆ P
RESET SPAN
HI STAT
∆
P
D A M P E R
I N C R
I N C R
TO DAMPER
ACTUATOR
TO MAIN AIR
SUPPLY
DIFFERENTIAL PRESSURE (FLOW)
LIMIT ADJUSTMENT WHEN T’STAT
PRESSURE IS HIGH (HI STAT)
(FACTORY SET AT 0.65 IN. WG.)†
†- FIELD ADJUSTMENT REQUIRED
DIFFERENTIAL PRESSURE (FLOW)
LIMIT ADJUSTMENT WHEN T’STAT
PRESSURE IS LOW (LO STAT)
(FACTORY SET AT 0 IN. WG.)†
ALL ADJUSTMENTS CCW TO INCREASE
(1/8”-5/32” FLATBLADE SCREWDRIVER)
RESET SPAN ADJUSTMENT
(FACTORY SET AT 5 PSI)
DAMPER ACTION SELECTION
(FACTORY SET AT NORMALLY OPEN)
NOTE: SCREW MUST BE TIGHT AND ARROWS
IN PERFECT ALIGNMENT FOR DEVICE TO FUNCTION PROPERLY.
LOOSEN SCREW TO
CHANGE DAMPER ACTION
(SUPPLIED IN N.O. POSITION)
GAGE TAP. LEAVE CAP ON UNLESS
CONNECTING GAGE FOR RESET
START OR RESET SPAN ADJUSTMENT
PUSH ON NIPPLES
FOR 3/16” (5) I.D.
FR TUBING (5)
* TO STATIC PRESSURE
TO TOTAL PRESSURE
*(DIFFERENCE IS: DIFFERENTIAL
PRESSURE, OR DEVICE
VELOCITY PRESSURE)
RESET START POINT ADJUSTMENT
(FACTORY SET AT 8 PSI)
TO THERMOSTAT BRANCH SIGNAL
(RESET SIGNAL)
Fig. 5 — CSC-3011 Controller