Carrier 19EF Series, Start Up & Operation Manual

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Table 4 — Capacity Overrides
OVERRIDE
CAPACITY
CONTROL
FIRST STAGE SET POINT
SECOND STAGE
SET POINT
OVERRIDE
TERMINATION
View/Modify
on LID Screen
Default Value Configurable Range Value Value
HIGH CONDENSER
PRESSURE
Equipment
Service1
125 psi
(862 kPa)
90 to 200 psi
(620 to 1379 kPa)
.
Override
Set Point
+ 4 psi (28 kPa)
,
Override
Set Point
HIGH MOTOR
TEMPERATURE
Equipment
Service1
.
200 F
(93.3 C)
150 to 200 F
(66 to 93 C)
.
Override
Set Point
+10° F (6° C)
,
Override
Set Point
LOW REFRIGERANT
TEMPERATURE
(Refrigerant Override
Delta Temperature)
Equipment
Service1
,
3° F (1.7° C)
(Above Trippoint)
2° to 5° F
(1° to 3° C)
<
Trippoint
+ Override
D
T –1° F
(0.56° C)
.
Trippoint
+ Override
D
T +2° F
(1.2° C)
HIGH COMPRESSOR
LIFT
(Surge Prevention)
Equipment
Service1
Min: T1 — 1.5° F
(0.8° C)
P1 — 50 psi
(345 kPa)
Max: T2 — 10° F
(5.6° C)
P2 — 85 psi
(586 kPa)
0.5° to 15° F
(0.3° to 8.3° C)
30 to 170 psi
(207 to 1172 kPa)
0.5° to 15° F
(0.3° to 8.3° C)
30 to 170 psi
(207 to 1172 kPa)
None
Within
Lift Limits
MANUAL
GUIDE VANE
TARGET
Control
Algorithm
Maint01
Automatic 0 to 100% None
Release of
Manual
Control
MOTOR LOAD —
ACTIVE
DEMAND LIMIT
Status01 100% 40 to 100%
>
105% of
Set Point
2% Lower
Than
Set Point
LEGEND
P1 — Minimum Pressure Load
P2 — Maximum Pressure Load
T1 — Minimum Temperature Load
T2 — Maximum Temperature Load
Oil Sump Temperature Control —
The oil sump tem-
perature control is regulated by the PIC which uses the oil
heater relay when the machine is shut down. The oil heater
relay is energized whenever the chiller compressor is off and
the oil sump temperature is less than 150 F (65.6 C) or the
oil sump temperature is less than the cooler refrigerant tem-
perature plus 70° F (39° C). The oil heater is turned off when
the oil sump temperature is either 1) more then 160 F
(71.1 C); or 2) the oil sump temperature is more than 155 F
(68.3 C) and more than the cooler refrigerant temperature
plus 75° F (41.6° C). The oil heater is always off during start-up
or when the compressor is running.
As part of the pre-start checks executed by the controls,
oil sump temperature is compared against evaporator refrig-
erant temperature. If the difference between these two tem-
peratures is 50 F (27.8 C) or less, the start-up will be delayed
until the oil temperature is 50 F (27.8 C) or more. Once this
temperature is confirmed, the start-up continues.
Oil Cooler —
The oil must be cooled when the compres-
sor is running. This is accomplished through a small, tube and
shell heat exchanger located beneath the compressor suction
housing. The heat exchanger uses chilled or condenser water
as the cooling liquid. A solenoid and cock valve regulate flow
to control oil temperature entering the bearings. The valve is
set to maintain 140 F (60 C) oil sump temperature.
Remote Start/Stop Controls —
A remote device, such
as a timeclock which uses a set of contacts, may be used to
start and stop the machine. However, the device should not
be programmed to start and stop the machine in excess of 2
or 3 times every 12 hours. If more than 8 starts in 12 hours
occur, then an Excessive Starts alert is displayed, preventing
the machine from starting. The operator must reset the alert
at the LID in order to override the starts counter and start the
machine. If Automatic Restart After a Power Failure is not
activated when a power failure occurs, and the remote con-
tact is closed, the machine will indicate an alarm because of
the loss of voltage.
The contacts for Remote Start are wired into the starter at
terminals 8A and 8B. See the certified drawings for further
details on contact ratings. The contacts must be dry (no power).
Spare Safety Inputs —
Normally closed (NC) digital
inputs for additional field-supplied safeties may be wired to
the spare protective limits input channel in place of the
factory-installed jumper. (Wire multiple inputs in series.) The
opening of any contact will result in a safety shutdown and
LID display. Refer to the certified drawings for safety con-
tact ratings.
Analog temperature sensors may also be added to the op-
tions modules, if installed. These may be programmed to pro-
vide an alert at the PIC or for CCN network, but will not
shut the machine down.
SPARE ALARM CONTACTS — Two spare sets of alarm
contacts are provided within the starter. The contact ratings
are provided in the certified drawings. The contacts are lo-
cated on terminals 5A and 5B and terminals 5C and 5D.
Condenser Pump Control —
The machine will moni-
tor the CONDENSER PRESSURE and may turn on this pump
if the pressure becomes too high whenever the compressor
is shut down. CONDENSER PRESSURE OVERRIDE is used
to determine this pressure point. This value is found on the
Equipment Service1 LID table and has a default value
(Table 4). If the CONDENSER PRESSURE is greater than
or equal to the CONDENSER PRESSURE OVERRIDE, and
the ENTERING CONDENSER WATER TEMP (Tempera-
ture) is less than 115 F (46 C), then the condenser pump will
energize to try to decrease the pressure. The pump will turn
off when the condenser pressure is less than the pressure over-
ride less 5 psi (34 kPa), or the CONDENSER REFRIG (Re-
frigerant) TEMP is within 3° F (2° C) of the ENTERING
CONDENSER WATER temperature.
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