Trane RTHD series Installation, Operation And Maintanance page 83

Table 24. Operating Modes
Chiller Modes
MP Resetting
Stopped
Local Stop
immediate Stop
Diagnostic Shutdown – Manual Reset
Run Inhibit
Diagnostic Shutdown – Auto Reset
Starting is Inhibited by External Source
Start Inhibited by BAS
Waiting for BAS Communications
Power Up Delay Inhibit
Low Differential Refrigerant Pressure Cool-
Down Timemin:sec
Auto
Waiting For Evap Water Flow
Waiting for A Need to Cool
Waiting to Start
Waiting For Cond Water Flow
Start Inhibited Waiting for Oil
Condenser Water Pump Pre-Run
Timemin:sec
Restart Inhibit min:sec
Waiting For EXV Preposition
Minimum Condenser Watermin:sec
Condenser Water Regulating Control
min:sec
Running
High Discharge Temp Limit
Base Loaded
Capacity Control Softloading
Current Control Softloading
Waiting For Heat Recovery Water Flow
RTHD-SVX02H-EN
Description
The chiller is not running and cannot run without intervention. Further information
is provided by the sub-mode:
Chiller is stopped by TD7 Stop button command– cannot be remotely overridden.
Chiller is stopped by the TD7 Panic Stop (by pressing Stop button twice in succession) – pre-
vious shutdown was manually commanded to shutdown immediately without a run-unload or
pumpdown cycle - cannot be remotely overridden.
The chiller is stopped by a diagnostic that requires manual intervention to reset.
The chiller is currently being inhibited from starting (and running*), but may be
allowed to start if the inhibiting or diagnostic condition is cleared. Further infor-
mation is provided by the sub-mode:
The entire chiller is stopped by a diagnostic that may automatically clear.
The chiller is inhibited from starting (and running) by the "external stop" hardwired input.
The chiller is inhibited from starting (and running) by command from a Building Automation
System via the digital communication link (com 4 or com 5).
This is a transient mode - 15-min. max, and is only possible if the chiller is in the Auto -
Remote command mode. After a power up reset, it is necessary to wait for valid communi-
cation from a Building Automation System (Tracer) to know whether to run or stay inhibit-
ed. Either valid communication will be received from the Building Automation System (e.g.
Tracer), or a communication diagnostic ultimately will result. In the latter case the chiller will
revert to Local control.
min:sec The compressor is currently being inhibited from starting as part of the power up start delay
(or staggered start) feature. This feature is intended to prevent multiple chillers from all
starting simultaneously if power is restored to all chillers simultaneously.
See Oil Flow Protection (Spec Page 78)
The chiller is not currently running but can be expected to start at any moment
given that the proper conditions and interlocks are satisfied. Further information is
provided by the sub-mode:
The chiller will wait up to 20 minutes in this mode for evaporator water flow to be established
per the flow switch hardwired input.
The chiller will wait indefinitely in this mode, for an evaporator leaving water temperature
higher than the Chilled Water Setpoint plus the Differential to Start.
The chiller is not currently running and there is a call for cooling but start is de-
layed by certain interlocks or proofs. Further information is provided by the sub-
mode:
The chiller will wait up to 20 minutes in this mode for condenser water flow to be established
per the flow switch hardwired input.
The chiller will wait up to 2 minutes in this mode for oil level to appear in the oil tank.
The chiller will wait up to 30 minutes (user adjustable) in this mode for to allow the condens-
er water loop to equalize in temperature
The compressor is currently unable to start due to its restart inhibit timer. A given com-
pressor 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.
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)
Only possible when Condenser Head Pressure Control option is enabled, this wait may be
necessary due to the Head Pressure control device's stroke time.
Only possible when Condenser Head Pressure Control option is enabled, this wait may be
necessary due to the Head Pressure control device's stroke time
The chiller, circuit, and compressor are currently running. Further information is
provided by the sub-mode:
The compressor is running and is being forced loaded to its step load point, without regard
to the leaving water temperature control, to prevent tripping on high compressor discharge
temperature.
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 re-
gard to the chilled water temperatures and the differential to start and stop
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.
The chiller is running, but loading is influenced by a gradual filter on the current limit set-
point The starting current and the settling time of this filter is user adjustable as part of the
softload control feature.
In this mode, the unit will wait for the establishment of heat recovery flow and the input of
the hardware interface of the flow switch.
Operator Interface Controls
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