Specifications
80
* CHILLED
WATER
PUMP
STARTERS
EWI-2
CP2
CP1
NOTE 11
NOTE 11
NOTE 11
*
NOTE 8
NOTE 8
NOTE 9
H
O
A
C4
* COOLING
TOWER
FIRST
STAGE
STARTER
* COOLING
TOWER
SECOND
STAGE
STARTER
* COOLING
TOWER
THIRD
STAGE
STARTER
* COOLING
TOWER
FOURTH
STAGE
STARTER
*
NOTE 10
H
A
O
C3
* NOTE 10
H
A
O
NOTE 10
NOTE 10
79
78
77
74
73
* REMOTE
ON/OFF
(NOTE 5)
54
86
86
C
CWI-2
CWI-1
(115V) (24V)
MICROTECH CONTROL
BOX TERMINALS
55
70
H
A
O
H
A
O
H
O
A
C
H
O
A
C
H
O
A
C
NOTE 11
NOTE 9
EWI-1
C2
C1
*
*
*
*
*
*
UTB1
MODE SWITCH
EF1
76
75
PE
85
86
POWER
NEUTRAL
NOTE 7
*
* CONDENSER
WATER
PUMP
STARTERS
EP2
EP1
GND
EVAP.
FLOW OR
DELTA P
SWITCH
(NOTE 6)
COND.
FLOW OR
DELTA P
SWITCH
(NOTE 6)
71
71
53
52
81
84
COMMON
POWER
A
82(NO)
83(NC)
NOTE 4
*
0-10 VDC
0-10 VDC
*COOLING TOWER VFD
*ALARM RELAY
(NOTE 4)
*COOLING TOWER BYPASS VALUE
CF1
EF2
CF2
Figure 15, Field Wiring Diagram
Field Wiring Diagram Notes
1. Compressor terminal boxes are factory-mounted and wired. All line-side wiring must be in accordance with the NEC and be made
with copper wire and copper lugs only. Power wiring between the terminal box and compressor terminals is factory installed.
2. Minimum wire size for 115 VAC is 12 ga. for a maximum length of 50 feet. If greater than 50 feet refer to McQuay for
recommended wire size minimum. Wire size for 24 VAC is 18 ga. All wiring to be installed as NEC Class 1 wiring system. All
24 VAC wiring must be run in separate conduit from 115 VAC wiring. Wiring must be wired in accordance with NEC and
connection to be made with copper wire and copper lugs only.
3. Voltage unbalance not to exceed 2% with a resultant current unbalance of 6 to 10 times the voltage unbalance per NEMA MG-1,
1998 Standard.
4. A customer furnished 24 or 120 vac power for alarm relay coil may be connected between UTB1 terminals 84 power and 81
neutral of the control panel. For normally open contacts wire between 82 & 81. For normally closed wire between 83 & 81. The
alarm is operator programmable. Maximum rating of the alarm relay coil is 25VA.
5. Remote on/off control of unit can be accomplished by installing a set of dry contacts between terminals 70 and 54.
6. If field supplied pressure differential switches are used, they must be installed across the vessel and not the pump. They must be
suitable for 24 vac and low current application.
7. Customer supplied 115 VAC 20 amp power for optional evaporator and condenser water pump control power and tower fans is
supplied to unit control terminals (UTB1) 85 power / 86 neutral, PE equipment ground.