Quantech QCC2015CEE Installation, Operation And Maintenance Manual page 31

Form QCC2-NM1
Issue Date: 5/20/2021
System run contacts
Contacts are available to monitor system status. Normal-
ly-open auxiliary contacts from each compressor contactor
are wired in parallel with XTBC2 – Terminals 25 to 26 for
system 1, and XTBC2 – Terminals 27 to 28 for system 2.
See Figure 4 on page 20, Figure 10 on page 37 and
the unit wiring diagrams starting on page 50.
Alarm status contacts
Normally-open contacts are available for each refriger-
ant system. These normally-open contacts close when
the system is functioning normally. The respective
contacts will open when the unit is shut down on a unit
fault, or locked out on a system fault. Field connections
are at XTBC2 - Terminals 29 to 30 (system 1), and Ter-
minals 31 to 32 (system 2).
Remote start/stop contacts
To remotely start and stop the chiller, dry contacts can
be wired in series with the flow switch and XTBC1 -
Terminals 13 to 51. See Figure 4 on page 20, Figure
10 on page 37 and the unit wiring diagrams starting on
page 50.
Remote emergency cutoff
Immediate shutdown of the chiller can be accom-
plished by opening a field-installed dry contact to
break the electrical circuit between Terminals 5 to L
on Terminal Block XTBC2. The unit is shipped with
a factory jumper installed between Terminals 5 to L,
which must be removed if emergency shutdown con-
tacts are installed. See Figure 10 on page 37 and the
unit wiring diagrams starting on page 50.
Remote temp reset input
The Remote Temp Reset input allows reset of the dis-
charge air temperature setpoint by supplying a voltage
or current signal field wiring should be connected to
XTBC1 – Terminals A+ to A-. A detailed explanation
is provided in the Unit Control section. See Figure 3 on
page 19, Figure 4 on page 20, and the unit wiring
diagrams starting on page 50.
Load limit input
Load limiting is a feature that prevents the unit from
loading beyond a desired value. (The unit can be "load
limited" either 33%, 40%, 50%, 66% or 80%, depend-
ing on the number of compressors on unit.) The field
connections are wired to XTBC1 – Terminals 13 to 21,
and work in conjunction with the PWM inputs. A de-
QUANTECH
tailed explanation is provided in the Unit Control sec-
tion. See Figure 4 on page 20, Figure 10 on page 37
and the unit wiring diagrams starting on page 50.
When using the Load Limit feature, the
PWM feature will not function – SIMUL-
TANEOUS OPERATION OF LOAD
LIMITING AND TEMPERATURE
RESET (PWM INPUT) CANNOT BE
DONE.
Liquid line solenoid connections
The field supplied and installed liquid line solenoid
valves should be installed at the evaporator and wired
using 18 AWG minimum wire. Electrical connections
should be made at Terminal Board TB1. TB1 is located
in the power panel on the left side of the power panel.
Note that power for the solenoid coil is 120 VAC.
See Figure 10 on page 37 and the unit wiring dia-
grams starting on page 50.
Discharge air sensor
The discharge air sensor and associated connector
hardware are field supplied and installed. Field wire
must be field supplied (QUABBIN 930421-2 or equiv-
alent 2 conductor with shield and drain wire - 20 AWG
300 V 60°C - polyethylene insulation UV resistant).
Field wiring is connected to pins 2, 5, and 8 of J6 on
the microboard. See Figure 4 on page 20, and the
unit wiring diagrams starting on page 50.
Zone thermostats, suction pressure control
only (remote start/stop)
Field supplied thermostats or dry contacts must be field
wired to start/stop the respective system when op‑
erating the unit in Suction Pressure Control Mode.
The System 1 zone thermostat is field wired at XTBC1
terminals 13 to 50. On two system units, System 2 zone
thermostat is field wired to XTBC1 terminals 13 to 51.
XTBC 1 terminal is located near the bottom of the mi-
cro control panel. See Figure 4 on page 20, and the
unit wiring diagrams starting on page 50.
SECTION 4 – INSTALLATION
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