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Table 19. Operating modes — chiller (continued)
Chiller Modes
Cold Ambient Start Inhibit – Waiting for
Warmer Water
Running
Chilled Water Control
Maximum Capacity
Capacity Control Softloading
Demand Limit Softloading
Shutting Down
Evaporator Water Pump Off Delay: MIN:SEC
Various
Manual Evap(orator) (Water) Pump Override
Diagnostic Evap (Water) Pump Override
Waiting for BAS Communications
Manual Compressor Control Signal
Noise Reduction
Chilled Water Control
These modes are mutually exclusive and they
indicate that the chiller is controlling to the
active hot water setpoint, the active chilled
water setpoint, or the active ice termination
setpoint respectively.
Ice Building
Note: Mode strings may or may not include the characters in parentheses.
Table 20. Operating modes — circuit
Circuit Modes
Stopped
Diagnostic Shutdown – Manual Reset
Front Panel Circuit Lockout
External Circuit Lockout
Service Pumpdown
AC-SVX001A-EN
Description
During startups with Outdoor Ambient temperatures less than 18°F, it may be necessary to
require warmer entering water to avoid a freeze danger at startup. The occurrence of this
mode suggests that startup is being inhibited pending warmer water temperatures than
otherwise would be required by the Differential to Start and Active Chilled Water
Temperature settings.
At least one circuit on the chiller is currently running.
Chiller is running to provide a chilled water temperature per the active chilled water setpoint
(may be as arbitrated from various sources). (For cooling only units, this mode may be
suppressed.)
The chiller is operating at its maximum capacity.
The control is limiting the chiller loading due to capacity based softloading setpoints.
The chiller is running, and loading of individual compressors may be limited by a gradual
filter of the chiller's softloading Demand Limit setpoint. The starting Demandlimit and the
settling time of this filter is user adjustable as part of the Demand control softload feature.
The mode will be displayed as long as the Demand Control Softloading limit is ramping or
"settling".
The chiller is still running but shutdown is imminent. The chiller is going through a
compressor run-unload or extended operational pumpdown of the lag circuit/compressor (or
all circuits simultaneously)
The Evaporator water pump is continuing to run past the shutdown of the compressors,
executing the pump off delay timer.
These submodes may be displayed in most of the top level chiller modes.
The Evaporator water pump relay is on due to a manual command.
The Evaporator water pump relay is on due to a diagnostic.
The chiller has not detected communication with the BAS. This mode is only supported by
LonTalk systems. Depending on configurations and Setpoint source setting, lack of
communication may cause the chiller to shut down and or become inhibited from starting,
but if so, the "Starting is Inhibited by BAS" mode will also occur.
Chiller capacity control is being controlled by AdaptiView or TU.
The Chiller's Noise Reduction Mode has been activated. The condenser fans may be limited to
a lower speed than design, to reduce fan noise.
Description
The circuit is not running, and cannot run without intervention.
The circuit has been shutdown on a latching diagnostic.
The circuit is manually locked out by the circuit lockout setting – the nonvolatile lockout
setting is accessible through either the AdaptiView or TU.
The respective circuit is locked out by the external circuit lockout binary input.
The circuit is currently performing a service pumpdown.
C C o o n n t t r r o o l l s s
55
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