22
5. Check that system static pressure is within acceptable
limits (minimum 1.2" WC - ,maximum 1.5" WC). You
can use a U-tube manometer to check the external sta-
tic pressure on the duct system.
1. Puncture a ¼" diameter hole in the plenum duct at
least 18" from the fan coil unit.
2. Insert the high-side manometer tube into the hole so
that the end is approximately flush with the inside wall
of the plenum, and perpendicular to the direction of airflow.
3. System static pressure should be between 1.2" and 1.5" WC.
a. If the pressure is higher than 1.5" provide additional
supply runs to increase airflow or lower the fan
speed by turning the fan speed adjustment for the
current mode of operation counter-clockwise to
reduce the static pressure.
b. If the pressure is lower than 1.2", look for leaks in
the supply plenum, restrictions in the return system
(including clogged filters) If more than the
recommended number of supply runs are installed,
you may install flow restrictors (orifices) in these
runs. If the number of runs is appropriate for the
load, increase the static pressure by turning fan
speed adjustment for the current mode of operation
clockwise to increase the static pressure.
6. Check that blower motor amp draw compares with
fan coil unit rating plate. Amp draw shown on plate is
the FLA of motor (not the actual running amps) and will
vary with the pressure and voltage.
7. Place the thermostat cooling indicator in COOL position,
which will start the outdoor unit. Let the system run at
least 30 minutes to stabilize operating conditions.
8. For outdoor unit start-up, follow manufacturer’s instructions.
FACTORS AFFECTING THE BALANCE OF THE SYSTEM
A. Room Terminators (Outlets): Based on the equip-
ment selected, determine the recommended number
of fully open outlets from Figure 3.1.
FIGURE 3.1
1. The minimum or recommended number of outlets
means fully open outlets. Any outlet having an orifice
would be only a percentage of an outlet.
2. For systems with average supply tubing lengths of 15'
or less, use column A. For systems with supply
tubing lengths greater than 15', use column B.
NOTICE: The number of outlets and average length of the
supply tubing has a significant effect on the over-all
system performance. It is highly recommended that the
adjustment factors outlined in the SpacePak Application
Manual are accounted for prior to any installation.
B. Orifice Combinations: Should orifices be required to
balance the system (installed at plenum take-off),
refer to the combinations listed in Figure 3.2.
FIGURE 3.2
C. Supply Tubing Length: An outlet with a supply
tubing length of 15' is considered one, fully
opened outlet. For other lengths refer to Figure
3.3 for adjustment factors.
FIGURE 3.3
2" SUPPLY TUBING LENGTH ADJUSTMENT FACTOR CHART
FACTOR
RUN
1.18
1.14
1.11
1.06
1.0
.9
.8
.66
6'
8'
10'
12'
15'
20'
25'
30'
DESIRED NUMBER
OF TERMINALS *
TERMINAL - ORIFICE
COMBINATION
.5
.65
.85
1.00
1.15
1.30
1.50
1.65
1.70
1.80
1.85
1.95
(1) .5
(1) .35
(1) .15
(1)
(1) .5 + (1) .35
(2) .35
(1) .35 + (1) .15 or (1) + (1) .5 or (3) .5
(1) + (1) .35 or (2) .5 + (1) .35
(2) .15
(2) .35 + (1) .5
(1) + (1) .15
(3) .35
2.00
(2)
*
For a room with more than two (2) terminals, combinations of the above
may be used to achieve the desired fractional number.
NOMINAL
TONNAGE
MODEL
WCSP-2430JV
WCSP-2430JV
WCSP-3642JV
WCSP-3642JV
WCSP-4860JV
WCSP-4860JV
2
2 1/2
3
3 1/2
4
5
A B
14
18
21
25
28
35
MINIMUM RECOMMENDED
NUMBER OF FULLY OPEN OUTLETS
12
15
18
21
26
30
Содержание WCSP-2430JV
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