Hot Gas Bypass Contactor Relay (3C) - Carrier 23xl Start-Up, Operation And Maintenance Instructions Manual

INTEGRATED STARTER MODULE (ISM) — This mod-
ule is located in the starter cabinet. This module initiates com-
mands from the CVC for starter functions such as starting and
stopping the compressor, condenser, chilled water pumps, tow-
er fan, spare alarm contacts, 4 to 20 mA Head Pressure Refer-
ence output, and the shunt trip. The ISM monitors starter inputs
such as line voltage, motor current, ground fault, remote start
contact, spare safety, condenser high pressure, starter 1M, and
run contacts. The ISM contains logic capable of safety shut-
down. It shuts down the chiller if communications with the
CVC are lost.
CHILLER CONTROL MODULE (CCM) — This module is
located in the control panel. The CCM provides the input and
outputs necessary to control the chiller. This module monitors
refrigerant pressure, entering and leaving water temperatures
and pressures, and outputs control for the slide valve oil heat-
ers, and oil pump. The CCM is the connection point for option-
al demand limit, chilled water reset, 4 to 20 mA kW output, re-
mote temperature reset, and refrigerant leak sensor.
OIL HEATER CONTACTOR (1C) — This contactor is lo-
cated in the power panel (Fig. 16) and operates the heater at ei-
ther 115 or 230 v. It is controlled by the PIC II to maintain oil
temperature during chiller shutdown.
HOT GAS BYPASS CONTACTOR
(Optional) — This relay, located in the power panel, controls
the opening of the hot gas bypass valve. The PIC II energizes
the relay during low load, high lift conditions.
CONTROL TRANSFORMERS (T1, T2) — These
formers convert incoming control voltage to 24 vac power for
the 3 power panel contactor relays, CCM, and CVC.
RELAY (3C)
17
Fig. 13 — Control Sensors (Temperature)
Fig. 14 — Control Sensors
(Pressure Transducers, Typical)
trans-