Hot Gas Bypass Contactor Relay (3C) (Optional)
This relay, locat ed in the power pa nel, controls t he opening of th e hot gas bypass valve. The
PIC energizes the relay dur i ng low load, high lift con ditions.
Oil Auxiliary Relay (4C)
This relay, supplied on ly with open-drive machi nes, opens the oil coole r solenoid valve and
interlocks the oil pump with the compressor.
Control Transformers (T1-T4)
These transformers are located in the power pan el an d convert incoming c ont rol voltage to
either 21 vac power for the PSIO module and option s mo dul es, or 24 vac power for 3 powe r
panel contactor relays and a control solen oid valve.
Control and Oil Heater Voltage Selector (S1)
It is necessary to use 115 v in c om in g control power in the powe r panel. The switch mus t be
set to the 115-v positi on.
Oil Differential Pressure /Power Supply Module
This module, whic h is located in the control cen ter, provides 5 vdc power for the transducers
and LID backli ght.
On open-drive machin es , this module outputs the di fference between two p ressure
transducer input signa ls. The module subtrac t s oil supply pressure from transmission su m p