Jetson FWCD Series, Installation Operation & Maintenance, Page: 18 / 96

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Digit 30 — Local Unit Controller Interface
0 = Keypad with Dot Pixel Display - keypad, 128 x 64 dot pixel STN monochrome graphics LCD
with 2.8" diagonal viewing area
B = 15.4-in. Color Touchscreen - Information and graphics are shown on high resolution
(1280x800) LCD display with LED back lighting. The high-resolution screen makes it easy for the
user to manage complex installations without losing the overall view or requiring a separate laptop.
Pages can be navigated in a fast and straightforward manner.
Digit 31 — Remote BMS Interface (Digital Comm)
0 = None
2 = Lon Talk®
4 = BACnet® MS/TP
5 = BACnet® IP
6 = MODBUS®
8 = Johnson N2
Digit 32 — Blank
0 = Blank
Digit 33 — Blank
0 = Blank
Digit 34 — Refrigeration Options
1 = Active Freeze Protection (All Circuits) – Active freeze protection is a suction pressure-based
freeze protection. Active Freeze Protection is standard on all FWCD Series chillers. The chiller’s
unit controller continually monitors the saturated suction pressure and will open (energize) the
Active Freeze Protection solenoid if the suction pressure falls to approximately 101 psig (32°F).
The solenoid closes (de-energizes) when the pressure climbs to approximately 105 psig (34°F) and
the freezing potential no longer exists.
2 = Hot Gas Bypass (All Circuits) - Hot gas bypass can stabilize the system balance point by
diverting hot, high- pressure refrigerant vapor from the discharge line directly to the low-pressure
side of the system. This tactic keeps the compressor more fully loaded while the evaporator satisfies
the part-load condition. The Jetson Active Freeze Protection can be configured to function as Hot
Gas Bypass by configuring the controller to monitor both the leaving water temperature and the
suction temperature. In Hot Gas Bypass operating mode, the Active Freeze Protection provides an
additional step of capacity.