36
Fig. 59 — 62X Sequence of Operations Flow Chart, Cooling Mode
IS
COMPRESSOR #1
DIGITAL?
NO
IS SYSTEM
IN ALARM OR
SHUTDOWN?
Compressor #2 takes over
for Compressor #1.
YES
alarm in Equipment Touch.
See IOM For more
YES
NO
IS
COMPRESSOR #2
INCLUDED?
YES
NO
COMPRESSOR #1
TURNS ON.
NO
IS SYSTEM
IN ALARM OR
SHUTDOWN?
alarm in Equipment Touch.
See IOM For more
YES
Y2 TURNS ON
COMPRESSOR #2
TURNS ON.
IS THERE A
DEMAND FOR 2
ND
STAGE COOLING?
YES
If Compressor #2 is included and on due
now been cleared, Compressor #2 will turn off,
IS HGRH
INCLUDED?
YES
IS THERE A CALL
FOR HGRH?
YES
IS HGRH
MODULATING?
YES
NO
HGRH TURNS ON.
HGRH TURNS ON AND MDV
MODULATES TO MAINTAIN
LAT COOLING SET POINT.
COMPRESSORS ARE SUBJECT TO A 4-MINUTE
MINIMUM RUN-TIME WHICH INITIATES WHEN
THE COMPRESSOR TURNS ON.
THE DCM MODULATES
COMPRESSOR #1 TO
MAINTAIN SLT COOLING
SET POINT.
Y1 TURNS ON
IS HGRH
INCLUDED ON BOTH
CIRCUITS?
YES
5 MINUTE DELAY
FIXED
start-up of controller.
COMPRESSORS ARE SUBJECT TO A 5-MINUTE
MINIMUM TIME OFF WHICH INITIATES WHEN
THE COMPRESSOR TURNS OFF.
FROM FIG. 58
