38
Normally, a closed system needs to be filled only once. The
actual filling process is generally a fairly simple procedure. All
air should be purged or vented from the system. Thorough
venting at the high points and circulation at room temperature
for several hours is recommended.
NOTE: Local codes concerning backflow devices and other
protection of the city water system should be consulted and
followed to prevent contamination of the public water
supply. This is especially important when antifreeze is used
in the system.
Set Water Flow Rate through the chiller once the system is
cleaned, pressurized, and filled.
NOTE: Carrier recommends a differential pressure gage when
measuring pressures across the pumps or balancing valves.
This provides for greater accuracy and reduces error build-up
that often occurs when subtracting pressures made by different
gages.
On primary/secondary systems, it is advisable to set the
30MP balancing valve to maintain design flow plus 10%
through the chiller.
A rough estimate of water flow can also be obtained from
measuring the pressure drop across the 30MP heat exchanger.
Figures 30-33 show the relationship between gpm (l/s) and
heat exchanger pressure drop. It should be noted that these
curves are for “clean” heat exchangers with fresh water; they
do not apply to heat exchangers with fouling or glycol. Adjust
the external balancing valve until the correct pressure drop is
obtained for the required gpm.
Step 7 — Make Electrical Connections —
All
field wiring must comply with local code requirements.
Electrical data for the complete unit and for the compressors is
shown in Tables 11-13. See Fig. 39 for field wiring connec-
tions. A field-supplied branch circuit disconnect switch that
can be locked in either OPEN or OFF position
must
be in-
stalled.
30MPA, MPW CONTROL BOX
30MPA, MPW Controls Section contains the following com-
ponents:
• main base board (MBB)
• scrolling marquee display
• optional energy management module
• control-circuit breakers for 24-v circuits
• control-circuit ON-OFF switch
• unit Enable/Off/Remote contact switch
• unit Alarm/Alert indicator light
30MPA, MPW Control Wiring (Factory-Wired) circuit
power is 24 v on all units. Factory-installed control transformer
(TRAN 1) uses line voltage for all units. All control transform-
ers are factory-installed and wired. For 208/230-3-60 units op-
erating at 208-3-60 line voltage, TRAN1 primary connections
must be moved to terminals H3 and H4 for 30MP016-045
units, or terminals H1 and H2 for 30MP050-071 units.
Inside the control box are terminals for field power and
ground (earth) wiring. A ground wire must be installed with
each field power supply. Compressors are wired for across-the-
line start. Refer to Tables 11-13 for electrical data.
30MPA, MPW, Control Wiring (Field-Wired) is found in
the 30MPA, MPW control box which contains the low-voltage,
field-wiring terminal strip (LVT). All low-voltage field-wiring
connections are made to this terminal block, see Fig. 39. Three
7
/
8
-in. (22 mm) knockouts are provided for field wiring in this
section.
Connections for condenser flow switch, chilled fluid pump
interlock, condenser pump interlock, remote alarm output, con-
denser output, and dual chiller thermistor accessory are made at
these locations. Connections for the multi-unit controller ac-
cessory network are made to the BACnet communication
module.
The unit has the capability to control field-supplied devices.
They are: alarm signal, condenser pump or condenser fan out-
put, and chilled water pump output. The unit provides 24-v
power with a maximum 5 va rating per output allowed.
30MPA, MPW Power Section supplies power to the 30MPA,
MPW unit. The electrical power supply is brought in through
the top left-hand side of the control box. Pressure-lug connec-
tions on the terminal blocks are suitable for only for copper
conductors.
The control box power section contains the following
components:
• power terminal block
• optional disconnect switch
• compressor circuit breaker(s)
• compressor contactor(s)
• current sensor boards
• control transformer
• ground lug
• neutral terminal (380-3-60, 380/415-3-50 units only)
• crankcase heater relay (30MPA, all units, 30MPW030 - 071)
• fuses
Flow Switches are provided on all units to provide a cooler
flow and are factory-installed and wired. A condenser flow
switch is available as an accessory for all 30MPW units, and
can be field-installed. The Carrier flow switch accessory (part
no. 30MP-900---004) is available for this purpose. Flow switch
wiring terminals are located in the field wiring compartment of
the control box. The flow switch should be wired between ter-
minals LVT-11 and LVT-17 for all units. Condenser water flow
switch cannot be used if a condenser water regulating valve is
installed.
30MPE DISTRIBUTION PANEL — Inside the panel are
terminals for field power and ground (earth) wiring. A ground
connection is available, and must be connected, in the 30MPE
panel for each chiller.
30MPE Distribution Panel, Power Section provides power to
the 30MPE distribution panel. The electrical power supply is
brought in through the top of the 30MPE distribution panel.
Pressure-lug connections on the terminal blocks or bus bar are
suitable for copper conductors only. The distribution panel
power section contains the following components:
• power terminal blocks or bus bar
• circuit breakers
• ground lugs
CAUTION
Failure to follow these instructions may result in unit dam-
age. When wiring the 30MP chiller to its associated
30MPE distribution panel, it is important to connect each
chiller to its corresponding circuit breaker in the panel.
Each circuit breaker has been sized for its particular chiller.
Proper installation is critical to ensure appropriate wire siz-
ing, hazard avoidance, and compliance with local code(s).
Consult submittal information.
