Carrier AQUASNAP MPW015-045 User Manual
Page 24
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may be entered for systems with brine solutions, but this value
should be set according to the freeze protection level of the
brine mixture. Failure to properly set this brine freeze point val-
ue may permanently damage the brazed plate heat exchanger.
The control will initiate Mode 7 (Circuit A) to indicate a cir-
cuit’s capacity is limited and that eventually the circuit may
shut down.
Operation of Machine Based on Control
Method and Cooling Set Point Selection Set-
tings —
Machine On/Off control is determined by the
configuration of the Control Method (Configuration
OPT2
CTRL) and Cooling Set Point Select
(Configuration
SLCT
CLSP) variables. All units are fac-
tory configured with Cooling Set Point Select set to 0 (single
set point). With the control method set to 0, simply switching
the Enable/Off/Remote Contact switch to the Enable or
Remote Contact position (external contacts closed) will put the
chiller in an occupied state. The control mode (Run
Status
VIEW
STAT) will be 1 (OFF LOCAL) when the
switch is Off and will be 5 (ON LOCAL) when in the Enable
position or Remote Contact position with external contacts
closed.
Two other control methods are available for Machine On/
Off control:
OCCUPANCY SCHEDULE (Configuration
OPT2
CTRL = 1) — The main base board will use the operating
schedules as defined under the Time Clock mode in the scroll-
ing marquee display. These schedules are identical. The sched-
ule number must be set to 1 for local schedule.
The schedule number can be set anywhere from 65 to 99
for operation under a CCN global schedule. The Enable/Off/
Remote Contact must be in the Enable or Remote Contact posi-
tion. The control mode (Run Status
VIEW
STAT) will be
1 when the switch is Off. The control mode will be 3 when the
Enable/Off/Remote Contact switch input is On and the time of
day is during an unoccupied period. Similarly, the control
mode will be 7 when the time of day is during an occupied
period.
CCN SCHEDULE (Configuration
OPT2
CTRL =
2) — An external CCN device such as Chillervisor System
Manager controls the On/Off state of the machine. This CCN
device forces the variable ‘CHIL_S_S’ between Start/Stop to
control the chiller. The control mode (Run Status
VIEW
STAT) will be 1 when the switch is Off. The con-
trol mode will be 2 when the Enable/Off/Remote Contact
switch input is On and the CHIL_S_S variable is ‘Stop.’
Similarly, the control mode will be 6 when the CHIL_S_S vari-
able is ‘Start.’
Table 20 illustrates how the control method and cooling set
point select variables direct the operation of the chiller and the
set point to which it controls. The illustration also shows the
ON/OFF state of the machine for the given combinations.
Cooling Set Point Select
SINGLE — Unit operation is based on Cooling Set Point 1
(Set Points
COOL
CSP.1).
DUAL SWITCH — Unit operation is based on Cooling Set
Point 1 (Set Points
COOL
CSP.1) when the Dual Set
Point switch contacts are open and Cooling Set Point 2 (Set
Points
COOL
CSP.2) when they are closed.
DUAL
CCN
OCCUPIED — Unit operation is based on
Cooling Set Point 1 (Set Points
COOL
CSP.1) during the
Occupied mode and Cooling Set Point 2 (Set
Points
COOL
CSP.2) during the Unoccupied mode as
configured under the local occupancy schedule accessible only
from CCN. Schedule Number in Table SCHEDOVR (See Ap-
pendix B) must be configured to 1. If the Schedule Number is
set to 0, the unit will operate in a continuous 24-hr Occupied
mode. Control method must be configured to 0 (switch). See
Table 20.
4 TO 20 mA INPUT — Unit operation is based on an external
4 to 20 mA signal input to the Energy Management Module
(EMM).
Cooler Pump Control —
The AquaSnap® 30MP ma-
chines are configured with the Cooler Pump Control (Configu-
ration
OPT1
CPC) = ON.
The maximum load allowed for the Chilled Water Pump
Starter is 5 VA sealed, 10 VA inrush at 24 volts. The starter coil
is powered from the chiller control system. The starter should
be wired between LVT 24 and TB3-1. If equipped, the field-in-
stalled chilled water pump starter auxiliary contacts should be
connected in series with the chilled water flow switch between
LVT 16 and LVT 17.
Ice Mode —
When Ice Mode is enabled Cooling Setpoint
Select must be set to Dual Switch, Dual 7 day or Dual CCN
Occupied and the Energy Management Module (EMM) must
be installed. Unit operation is based on Cooling Setpoint 1
(CSP.1) during the Occupied mode, Ice Setpoint (CSP.3) dur-
ing the Unoccupied mode with the Ice Done contacts open and
Cooling Setpoint 2 (CSP.2) during the Unoccupied mode with
the Ice Done contacts closed. These 3 set points can be utilized
to develop your specific control strategy.
Service Test (See Table 4) —
Both main power and
control circuit power must be on.
The Service Test function should be used to verify proper
operation of condenser output, compressors, minimum load
valve solenoid (if installed), cooler pump, and remote alarm re-
lay. To use the Service Test mode, the Enable/Off/Remote Con-
tact switch must be in the OFF position. Use the display keys
and Table 4 to enter the mode and display TEST. Press
twice so that OFF flashes. Enter the password if re-
quired. Use either arrow key to change the TEST value to the
ON position and press
. Press
and the
button to enter the OUTS or COMP sub-mode.
Table 20 — Control Methods and Cooling Set Points
*Dual set point switch input used. CSP1 used when switch input is open. CSP2 used when switch input is closed.
†Cooling set point determined from 4 to 20 mA input to energy management module (EMM) to terminals TB6-3,5.
ENTER
ENTER
ESCAPE
CONTROL
TYPE
(CTRL)
OCCUPANCY
STATE
COOLING SET POINT SELECT (CLSP)
0
(single)
1
(dual, switch)
2
(dual, occ)
3
(4 to 20 mA)
0 (switch)
Occupied
ON,CSP1
ON*
ON,CSP1
ON†
Unoccupied
ON,CSP1
ON*
ON,CSP2
ON
2 (Occupancy)
Occupied
ON,CSP1
ON*
Illegal
ON†
Unoccupied
OFF
OFF
Illegal
OFF
3 (CCN)
Occupied
ON,CSP1
ON*
ON,CSP1
ON†
Unoccupied
ON,CSP1
ON*
ON,CSP2
ON†