Specifications

CONDENSER PUMP CONTROL ( ) — Factory de-
faults for both condenser pump control and condenser flow
switch are set to ‘‘Not Controlled’’ and ‘‘Disabled,’’ respec-
tively. The condenser pump can be controlled in one of two
ways: In the first method, the pump can be controlled like
the cooler pump — it is turned on whenever the machine is
in the on state and turned off otherwise (set to Type 1 using
the Service function). The second method of control is to
turn the pump on when the first compressor is started and off
when the last compressor is turned off (set to Type 2 using
the Service function). With the flow switched enabled, the
control checks the status of the input one minute after start-
ing the pump. An alarm is generated if the flow switch input
is not closed.
READ CIRCUIT
SATURATED
CONDENSING
TEMPERATURE
AND CURRENT
FAN STAGE
IS SCT GREATER
THAN HEAD
PRESSURE
SET POINT?
INCREASE
CURRENT FAN
STAGE BY ONE
ADD 15° F TO
HEAD PRESSURE
SET POINT FOR
NEXT 35 SECONDS
DECREASE
CURRENT FAN
STAGE BY ONE
HAS SCT BEEN 35° F
LESS THAN HEAD
PRESSURE SET POINT
2 MINUTES?
NO
NO
YES
YES
LEGEND
SCT — Saturated Condensing Temperature
Fig. 6A — 30GX Head Pressure Control Without MotormasterT III Control
30GX UNITS — MOTORMASTER III CONTROL NOT INSTALLED
30GX UNITS — MOTORMASTER III CONTROL INSTALLED
DECREASE
CURRENT FAN
STAGE BY ONE
NO
NO
YES
IS SCT GREATER
THAN HEAD
PRESSURE SET
POINT PLUS 15F?
INCREASE
CURRENT FAN
STAGE BY ONE
YES
READ CIRCUIT
SATURATED
CONDENSING
TEMPERATURE
AND CURRENT
FAN STAGE
NO
INCREASE
CURRENT FAN
STAGE BY ONE
YES
CALCULATE NEW
PID VALUE. DOSE
OUTPUT REQUIRE
MORE FANS?
OUTPUT NEW mA
SIGNAL TO
CONTROLLER
DOES PID OUTPUT
REQUIRE LESS
FANS?
LEGEND
PID — Proportional Integral Derivative
SCT — Saturated Condensing Temperature
Fig. 6B — 30GX Head Pressure Control With Motormaster III Control
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