Installation and Maintenance Manual

Controls Interface
136 RLC-SVX09H-EN
Table 108. Circuit modes
Circuit Modes Description
Top Level Mode Further information is provided by the submode
Sub-modes
Stopped The given circuit is not running and cannot run without intervention.
Stopped Sub-modes
Diagnostic Shutdown - Manual Reset The circuit has been shutdown on a latching diagnostic.
Front Panel Circuit Lockout
The circuit is manually locked out by the circuit lockout setting - the nonvolatile
lockout setting is accessible through either the DynaView or TechView.
External Circuit Lockout The respective circuit is locked out by the external circuit lockout binary input.
Run Inhibit
The given circuit is currently being inhibited from starting (and running), but may
be allowed to start if the inhibiting or diagnostic condition is cleared.
Run Inhibit Sub-modes
Diagnostic Shutdown - Auto Reset The circuit has been shutdown on a diagnostic that may clear automatically.
Low Oil Flow Cool Down Time min:sec See oil flow protection spec
Restart Inhibit min:sec
The compressor (and therefore, its circuit) 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, once a number of "free starts" have been used up.
Auto
The given circuit is not currently running but can be expected to start at any
moment given that the proper conditions and interlocks are satisfied.
Auto Sub-mode
Calibrating EXV
This submode is displayed when the EXV is performing a calibration. A calibration
is only performed when the chiller is not running and never more frequently than
once every 24 hours
Waiting to Start The chiller is going through the necessary steps to allow the lead circuit to start.
Waiting to Start Sub-modes
Start Inhibited Waiting For Oil
The compressor (and thus its circuit) will wait up to 2 minutes in this mode for oil
level to appear in the oil tank.
Waiting For EXV Preposition
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 The compressor on the given circuit is currently running.
Running Sub-modes
Establishing Min Cap - Low Diff Pressure
The circuit is experiencing low system differential pressure and its compressor is
being force loaded, regardless of Chilled Water Temperature Control, to develop
pressure sooner.
Establishing Min Cap - High Disch Temp
The circuit is running with high discharge temperatures and its compressor is being
force loaded to its step load point, without regard to the leaving water temperature
control, to prevent tripping on high compressor discharge temperature.
EXV Controlling Differential Pressure
Liquid level control of the Electronic Expansion Valve has temporarily 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 only as is necessary to provide minimum oil flow for the compressor until the
condenser water loop can warm up to approximately 50F. (Future mode display -
display of mode not implemented in Phase 1 or 2 although present in algorithms.)
EXV Controlling for Low Evaporator Pressure
Liquid level control of the Electronic Expansion Valve has temporarily been
suspended. The EXV is being modulated to control for a minimum evaporator
pressure that is based on the pressure of the Low Refrigerant Temperature Cutout.
This control will tend to increase the liquid level above the setpoint or to open the
valve more quickly than liquid level control can, in order to avoid an LRTC trip. It
is most often invoked transiently to help open the EXV in the event of rapidly falling
liquid level and rapidly declining evaporator pressures. (Future Mode display -
display of mode not implemented in Phase 1 or 2 although present in algorithms.)
Running - Limited
The circuit, and compressor are currently running, but the operation of the chiller/
compressor is being actively limited by the controls. * See the section below
regarding criteria for annunciation of limit modes
Running-Limited Sub-modes