26
Table 15 — Operational and Mode Display Codes
*A field-supplied 500 Ohm
1
/
2
W resistor must be installed across
the input terminals when using a 4 to 20 mA signal.
Table 16 — Reading Current Operating Mode
CODE
DESCRIPTION
LOCAL OFF
Unit is off. LOCAL/OFF/REMOTE switch is in OFF
position or LOCAL/OFF/REMOTE switch is in
REMOTE position and remote contacts are open.
CCN OFF
Unit is off. LOCAL/OFF/REMOTE switch is in
LOCAL position and CCN control is enabled (Stop
state) or CCN is enabled (Stop state) with LOR
switch in REMOTE position and remote contacts
closed.
CLOCK OFF
Unit is off due to internal clock schedule. LOR
switch is in LOCAL position.
LOCAL ON
Unit is on. LOR switch is in LOCAL position and
CCN is disabled or LOR switch is in REMOTE
position with contacts closed and CCN is disabled.
CCN ON
Unit is on due to CCN command. LOR switch is in
LOCAL position and CCN is enabled (Run state)
or LOR switch is in REMOTE position with con-
tacts closed and CCN is enabled (Run state).
CLOCK ON
Unit is on due to internal clock schedule or occu-
pied override function. LOR switch is in LOCAL
position.
DUAL SP ACTIVE
(1st SP)
Dual set point is in effect. In this mode, unit contin-
ues to run in an occupied condition, and leaving
fluid set point is automatically controlled to the
CSP1 set point in the SET POINT function.
DUAL SP ACTIVE
(2nd SP)
Dual set point is in effect. In this mode, unit contin-
ues to run in unoccupied condition, but leaving
fluid set point is automatically increased to a
higher level (CSP2 set point is in SET POINT
function).
TEMPERATURE
RESET ACTIVE
Temperature reset is in effect. In this mode, unit is
using temperature reset to adjust leaving fluid set
point upward, and unit is currently controlling to
the modified set point. The set point can be modi-
fied based on return fluid, outdoor-air temperature,
space temperature, or 4 to 20 mA signal.*
DEMAND LIMIT
ACTIVE
Demand limit is in effect. This indicates that
capacity of unit is being limited by demand limit
control option. Because of this limitation, the unit
may not be able to produce the desired leaving
fluid temperature. Demand limit can be controlled
by a switch or 4 to 20 mA signal.*
FSM
CONTROLLING
Flotronic™ System Manager (FSM) is controlling
the chiller.
RAMP LOADING
ACTIVE
Ramp load (pulldown) limiting is in effect. In this
mode, the rate at which leaving fluid temperature
is dropped is limited to a predetermined value to
prevent compressor overloading. See CRAMP set
point in the SET POINT function (page 27). The
pulldown limit can be modified, if desired, to any
rate from 0.2° F to 2° F (0.1° to 1° C)/minute.
TIMED OVERRIDE
ACTIVE
Timed override is in effect. This is a 1 to 4 hour
temporary override of the programmed schedule,
forcing unit to occupied mode. Override can be
implemented with unit under LOCAL/REMOTE or
CCN control. Override expires after each use.
WSM
CONTROLLING
Water System Manager is controlling the chiller.
SLOW CHANGE
OVERRIDE
Slow change override is in effect. The leaving fluid
temperature is close to and moving towards the
control point.
LEGEND
CCN
— Carrier Control Network
CSP
— Cooling Set Point
CRAMP — Cooling Ramp Loading
EXV
— Electronic Expansion Valve
LOR
— Local/Off/Remote
SP
— Set Point
WSM
— Water System Manager
CODE
DESCRIPTION
OFF TO ON
DELAY ACTIVE
Chiller is being held off by Minutes Off Time found by
keying
. Also, normal operation of the chiller
includes a minimum 1.5 minute delay after a capacity
stage change has been made. This delay is adjustable
from 1.5 to 6 minutes.
LOAD LIMIT
ACTIVE
This function determines the maximum allowable
capacity that can be running and is accomplished
through the Flotronic System Manager. The unit may
not be able to produce the desired leaving fluid
temperature.
2 CHILLR LEAD
LAG ACTIVE
This mode indicates that Master and Slave chillers
have been configured and are operating using the
Dual Chiller control. This is a series water flow
arrangement where chilled fluid is piped to the Slave
Chiller first and then through the Master Chiller.
Leaving Fluid Temperature control is performed based
on Master Chiller Leaving Fluid Temperature.
2 CHILLR LL
COMM FAILURE
This mode indicates that communication has been lost
between the Master and Slave chillers. Both
chillers will return to a stand-alone mode of operation
until communication is restored.
CIRCUIT A LOW
DISCHARGE
SUPERHT
If the discharge superheat is less than 5° F (2.8° C)
and falling, a circuit loader will be deenergized every
30 seconds. The final stage will not be unloaded
unless an alarm condition is present.
CIRCUIT B LOW
DISCHARGE
SUPERHT
See description for Circuit A above.
CIRCUIT A
HIGH SCT
If the circuit is running and the Saturated Condensing
Temperature (SCT) is greater than the Maximum
Condensing Temperature Set point (MCT_SP) minus
12° F (6.7° C), the control will not add any stages.
If the SCT is greater than the MCT_SP plus 5° F
(2.8° C), the circuit will be unloaded and shut down if
necessary. If the SCT is greater than the MCT_SP
plus 2° F (1.1° C) for one minute, a loader will be
deenergized.
If the SCT is greater than the MCT_SP minus 4° F
(2.2° C), the control will compare the maximum
operating pressure set point (MOP_SP) with the modi-
fied MOP_SP (MOP_CTRL).
If the MOP_CTRL is greater than the MOP_SP, the
mode will be cleared. Otherwise the control will
display the high SCT override mode. The capacity
control routine will not add any stages. If the circuit is
at its lowest capacity, this mode will be ignored.
CIRCUIT B
HIGH SCT
See description for Circuit A above.
LOW COOLER
SUCTION
TEMPERATURE
Circuit A and/or B low saturated suction condition
exists. Control will not increase capacity on affected
circuits. The EXV of the affected circuit(s) will be
opened until the condition does not exist.
KEYPAD ENTRY
DISPLAY
MODES :MODE_TBL
CCN ON
DEMAND LIMIT
ACTIVE
