Trane RTHD

90 RTHD-SVX01D-EN
Operator Interface Controls
Compressor Restart Inhibit Time
2
min:sec
The compressor is currently unable to start due to its restart inhibit
timer. A given compressor is not allowed to start until 5 minutes
(adj) has expired since its last start.
Waiting For EXV Preposition
2
The Chiller will wait for the time it takes the EXV to get to its
commanded pre-position prior to starting the compressor. This is
typically a relatively short delay and no countdown timer is
necessary (less than 15 seconds).
Running
1
The chiller, circuit, and compressor are currently running. Further
information is provided by the sub-mode:
Unit is Building Ice
2
The chiller is running in the Ice Building Mode, and either at or
moving towards full capacity available. Ice mode is terminated
either with the removal of the ice mode command or with the return
brine temperature falling below the Ice Termination Setpoint.
Establishing Min Capacity - High Disch
Temp
2
The compressor is running and is being forced loaded, without
regard to the leaving water temperature control, to prevent tripping
on high compressor discharge temperature.
Base Loaded
2
Chiller is running in "Base Load" operation where the capacity of
the chiller is controlled to maintain a given current per an
adjustable set point. The chiller is forced to run without regard to
the chilled water temperatures and the differential to start and stop.
Capacity Control Softloading
2
The chiller is running, but loading is influenced by a gradual
'pulldown" filter on the chilled water temperature setpoint The
settling time of this filter is user adjustable as part of the softload
control feature.
Current Control Softloading
2
The chiller is running, but loading is influenced by a gradual filter
on the current limit setpoint The starting current and the settling
time of this filter is user adjustable as part of the softload control
feature.
EXV Controlling Differential Pressure
2
Liquid level control of the Electronic Expansion Valve has tempo-
rarily been suspended. The EXV is being modulated to control for a
minimum differential pressure. This control implies low liquid
levels and higher approach temperatures, but is necessary to
provide minimum oil flow for the compressor until the condenser
water loop can warm up to approx 50F.
Running - Limited
1
The chiller, circuit, and compressor are currently running, but the
operation of the chiller/compressor is being actively limited by the
controls. Further information is provided by the sub-mode.
Capacity Limited by High Cond Press
2
The circuit is experiencing condenser pressures at or near the
condenser limit setting. The compressor will be unloaded to
prevent exceeding the limits.
Capacity Limited by Low Evap Rfgt
Temp
2
The circuit is experiencing saturated evaporator temperatures at or
near the Low Refrigerant Temperature Cutout setting. The
compressors will be unloaded to prevent tripping.
Table 18 Operating Modes
Chiller Modes Description
1 - Top Level Mode
2 - Sub Level Mode