Starter Type - McQuay MicroTech Unit Controller Installation And Maintenance Data

Wiring Notes
1.
Compressor motor starters are either factory mounted and wired
or shipped separate for field mounting and wiring. If provided by
others, starters must comply with McQuay specification 359A999
or 7515A69. All line and load side power conductors must be
copper.
2. If starters are free standing then field wiring between the starter
and the control panel is required. Minimum wire size for 115V
AC is 12 GA. for a maximum length of 50 feet. If greater than
50 feet refer to McQuay for recommended wire size. Wire size
for 24V AC is 18 GA. All wiring to be installed as NEC Class I
wiring system. All 24V AC wiring must be run in separate con-
duit from 115V AC wiring.
3. Optional reset of chilled water temperature or reset of motor cur-
rent limit can be accomplished by wiring 4-20 MA DC as shown.
If customer supplied transmitter does not have a power supply,
then a 17V DC unregulated power supply can be obtained at ter-
minal X67 of the control panel. It is recommended that transmit-
ter wires be run separately from the 115V AC wiring.
4.
An optional customer supplied 24V AC, 25 VA maximum rated
alarm relay can be wired as shown. The circuit will be de-
energized if any safety shutdown occurs.
5.
Remote ON/OFF control of units for multiple unit applications can
be accomplished by installing a set of dry contacts between ter-
minals 9 and 64. If an additional point of ON/OFF control is re-

STARTER TYPE

McQuay Centrifugal chillers are primarily designed for use
with Star-Delta and auto-transformer starters requiring a tran-
sition between starting stages.
They can also be used with across-the-line starters where
quired. remove jumper J6 from terminals 64 and 65 and install
the additional set of dry contacts.
6.
Evaporator and condenser water pressure differential or pad-
dle type flow switches are required and must be wired as shown.
If field supplied pressure differential switches are used then
these must be installed across the vessel and not the pump.
7.
Oil cooler solenoid valve (ASCO) model -8210827 is required
on some models. If not factory installed, refer to the installa-
tion manual and wire as shown.
8. An optional customer supplied 115V AC maximum coil rated
chilled water pump relay (CHWR) may be wired as shown. This
option will cycle the chilled water pump in response to building
load
9
The condenser water pump must cycle with the unit. A customer
supplied 115V AC, 25VA maximum coil rated condenser water
pump relay (CWR) is to be wired as shown.
10. Optional customer supplied 115V AC, 25 VA maximum coil rated
cooling tower fan relays (Cl, C2) may be wired as shown. This
option will cycle the cooling tower fans in order to maintain unit
head pressure.
11. Auxilliary 24V AC rated contacts in both the chilled water and
condenser water pump starters must be wired as shown.
ALL WIRING to be NEC Class 1.
no transition takes place. In this event (i.e., there is no transi-
tion in the starter), it is necessary that a normally open aux-
illary contact on the starter be wired between control panel
terminals numbered 11 and 12.
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