Trane CVGF500 Installation, Operation & Maintenance Manual page 107

This limit allows the chiller to continue to run at a reduced load.
Evaporator Limit uses the Evaporator Refrigerant Temperature sensor in a PID algo-
rithm (similar to the Leaving Water Temperature control) that allows the chiller to run
at the LRTC + 2 degree F (1.1°C).
When actively limiting machine control "Evaporator Temperature Limit" will be dis-
played as a suboperating mode.
Leaving Water Temperature Cut-out
Leaving water temperature cutout is a safety control that protects the chiller from
damage caused by water freezing in the evaporator. The cutout setpoint is factory set
at 36°F (2.2°C) however is adjustable with UT ™. The cut-out strategy is illustrated in
Figure 39.
The Leaving Water Temperature Cut-out Setpoint is independently adjustable from the
chilled water setpoint. Shutdown of the compressor due to violation of the Leaving
Water Temperature Cut-out results in an automatically resettable diagnostic (MAR).
The Large display ™ Operating Mode indicates when the Leaving Water Temperature
Cut-out Setpoint conflicts with the chilled water temperature setpoint by a message
on the display. The Leaving Water Temperature Cutout Setpoint and chilled water set-
point, both active and front panel, are separated by a minimum of 1.7°F (0.94°C). (See
Cut-out Strategy Figure 39.) When either difference is violated, the AdaptiView does
not permit the above differences to be violated and the display exhibits a message to
that effect and remains at the last valid setpoint. After violation of the Leaving Water
Temperature Cut-out Setpoint for 30°F (16.7°C) seconds the chiller will shutdown and
indicate a diagnostic.
Low Refrigerant Temperature Cut-out
The purpose of the low evaporator refrigerant temperature protection is to prevent
water in the evaporator from freezing. When the LRTC trip point is violated, a latching
diagnostic indicating the condition is displayed. The LRTC Diagnostic is active in both
the Running and Stopped modes.
CVGF-SVX03B-EN
Machine Protection and Adaptive Control
107