6-Pack Relay B oard
This device is a cluster of 6 pilot relays located in t he c on trol center. It is ene r giz e d by the
PSIO for the oil pump, oil he ater, alarm, optional hot gas bypass relay, and motor cooling
solenoid (19EX machine s) on auxiliary oil pu m p ( 17E X m ac h ines).
8-Input Modules
One optional modu le is factory in stalled in th e control center panel when orde red. There can
be up to 2 of these modules per c hil ler with 8 spare inputs eac h . They are used whenev er
chilled water reset, demand reset, or reading a s pa re sensor is required. The sensors or 4 to
20 mA signals are field-i nstalled.
The spare temperature sensors must have the same temperature/resistance curve as the
other temperature sen sors on this unit. These sensors are rated 5,000 ohm at 75 F (25 C).
Oil Heater Contactor (1C)
This contactor i s located in t he power panel and operates the heater at 115 v. It is cont rolled
by the PIC to maintain oil t em pe rature during machin e shutdown.
Oil Pump Contactor (2C)
This contactor is locat ed in the power panel. It oper a tes all 200 to 575-v oil pum ps . The PIC
energizes the contact or to turn on the oil pump as ne cessary.