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PNEUMATIC CONTROLS
General — Single Function Pneumatic Control-
ler Control Sequences (1300-1305, 1400-1401)
To properly balance the system, all ductwork and outlets must be
installed and connected tightly. Refer to piping/wiring diagram on
unit for specifics for the control sequence selected for the unit.
Units with Single-Function Controllers
1.
Determine sequence of operations (reverse-acting, nor-
mally closed [RANC], direct-acting, normally open
[DANO]). This can be accomplished by reading the dia-
gram affixed to the unit. The standard RANC controller is
gray colored; the DANO controller is beige. See Fig. 14-
16.
2.
Check that main air pressure at the controller. Main air
should equal 18 to 25 psi. Main air must be clean and dry.
3.
Check for primary airflow in the inlet duct, using a differ-
ential pressure sensor tapped into the differential pressure
sensor signal line tees.
4.
Verify that the installed room thermostat is compatible
with the unit control.
5.
Close the primary air damper.
a. RANC — disconnecting the actuator from the controller
should allow the damper to close completely.
b. DANO — connecting to 20 psi air supply directly to the
actuator should close the damper completely.
6.
Start the blower motor by doing one of the following:
45J,K,Q Units:
Both RANC and DANO — Connect electrical power to the
blower motor control.
45M,N,R Units:
RANC — Connect the main air line to the blower control,
bypassing the thermostat input.
DANO — Disconnect the thermostat line from the blower
controls.
These steps should energize the fan.
LO
CS C- 20 03
0- 1" P
D. A.
Fig. 14 — Pneumatic Volume Controller (Normally
Open) for Pneumatic Control Unit (Beige Color)
CS C- 20 04
0- 1" P
R. A.
Fig. 15 — Pneumatic Volume Controller (Normally
Closed) for Pneumatic Control Unit (Gray Color)
H
B
NO
M
D A M P E R
Fig. 16 — CSC 3000 Series Reset Volume Controller
7.
Balance the supply outlets using a proportional air volume
method.
a. With the blower discharging full volume (SCR on max
setting), measure the total air volume.
b. Calculate the percentage of the design air volume needed
by each outlet.
c. Multiply the total air volume by the percent-of-design air
volume for each diffuser.
d. Balance each outlet according to the requirements calcu-
lated above.
8.
Balance the unit fan discharge:
a. Measure the total flow discharging from the unit.
b. Adjust the discharge flow from the unit using the unit
electronic speed control (SCR).
9.
Reconnect the damper actuator and/or the thermostat tub-
ing to the velocity controller with the fan still running.
Make sure the piping is as shown on the unit piping/wiring
diagram.
10. Balance the primary (cooling) air volume:
NOTE: To balance the primary air side of the 45M,N,R unit
only, the blower motor must be disconnected.
a. Connect the Magnehelic or inclined manometer (0 to 2.0
in. wg scale, maximum) to the differential pressure sen-
sor tubing.
b. Measure the volume of air flowing through the inlet
using the calibration curve affixed to the unit.
RANC
a. With a 0 psi thermostat signal, measure the unit maxi-
mum airflow.
b. Rotate to the "HI" adjustment knob on the velocity con-
troller, adjust the airflow to the desired maximum
setting.
33
LO
T
L
RESET START
LO STAT ΔP
HI STAT ΔP
RESET SPAN
G
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