Carrier 50FK - Manual (Page 25)

MODULATING POWER EXHAUST — The tubing for the
building pressure control (achieved via the Modulating Power
Exhaust option) should sample building pressure in the area
near the entrance lobby (or other appropriate and sensitive
location) so that location is controlled as closely to design
pressures as possible.
A differential pressure switch (DPS) is used to control the
actuator on the modulating discharge damper in exhaust fan
no. 1. The building pressure (BP) DPS is located in the aux-
iliary control box of the unit. See Fig. 33 and 35. Use a nomi-
nal
3 ⁄
8
-in. plastic tubing.
For instructions on adjusting BP control set points, refer
to Start-Up, Modulating Power Exhaust section in this book.
START-UP
Initial Check
IMPORTANT: Do not attempt to start unit, even mo-
mentarily, until all items on the Controls Start-Up Check-
list (in installation instructions) and the following steps
have been completed.
1. Verify unit has been installed per the Installation Instruc-
tions included in the unit installation packet.
2. Verify that all auxiliary components (sensors, controls,
etc.) have been installed and wired to the unit control boxes
per these instructions, the unit Installation Instructions,
and the unit wiring label diagrams.
3. Verify that air pressure hoses (static, duct, etc.) are prop-
erly attached, routed, and free from pinches or crimps that
may affect proper control operation.
4. Set any control configurations that are required (field-
installed accessories, etc.). The unit is factory configured
for all appropriate factory-installed options with the ap-
plicable controls programmed to the default values.
5. Check and adjust unit set points. See Table 9.
6. Check tightness of all electrical connections.
7. Perform quick test (see Quick Test Program section on
page 31).
Fig. 33 — Modulating Power Exhaust and Inlet
Guide Vane Differential Pressure Switch
(Sizes 034-048)
Fig. 34 — Inlet Guide Vane Differential
Pressure Switch and Variable Frequency Drive
Duct Pressure Transducer (Sizes 054-104)
Fig. 35 — Modulating Power Exhaust Differential
Pressure Switch (Sizes 054-104)
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