Carrier 17 Start Up & Operation Manual Download

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Table 4 — Capacity Overrides

OVERRIDE

CAPACITY

CONTROL

FIRST STAGE SETPOINT

SECOND STAGE

SETPOINT

OVERRIDE

TERMINATION

View/Modify

on LID Screen

Default Value

Configurable Range

Value

HIGH CONDENSER

PRESSURE

Equipment

Service1

125 psig

(862 kPa)

90 to 200 psig

(620 to 1379 kPa)

Override

Set Point

+ 4 psid (28 kPad)

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 (1.6° C)

(Above Trippoint)

2° to 5° F

(1° to 3° C)

Trippoint

+ Override

T –1° F

(0.56° C)

Trippoint

+ Override

T +2° F

(1.2° C)

HIGH COMPRESSOR

LIFT

(Surge Prevention)

Equipment

Service1

Min: T1 — 1.5° F

(0.8° C)
P1 — 50 psid
(345 kPad)

Max: T2 — 10° F

(5.6° C)
P2 — 85 psid
(586 kPad)

0.5° to 15° F

(0.3° to 8.3° C)

30 to 170 psid

(207 to1172 kPad)

0.5° to 15° F

(0.3° to 8.3° C)

30 to 170 psid

(207 to 1172 kPad)

None

Within

Lift Limits

Plus Surge/

HGBP

Deadband

Setting

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%

5% 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
*Not available on open drive machines.

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.

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 2 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.

The oil heater relay is energized whenever the chiller com-

pressor 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 temperature plus 70° F (39° C). The oil
heater is turned off when the oil sump temperature is either
1) more than 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.

When a power failure to the PSIO module has occurred

for more than 3 hours (i.e., initial start-up), the compressor
guide vane opening will be slowed down to prevent exces-
sive oil foaming that may result from refrigerant migration
into the oil sump during the power failure. The vane opening
will be slowed to a value of 2° F (1.1° C) per minute with
temperature ramp loading.

Oil Cooler —

The oil must be cooled when the compres-

sor is running.

EX Compressors: This is accomplished through a small, plate-
type heat exchanger. The heat exchanger uses liquid con-
denser refrigerant as the cooling liquid. A refrigerant ther-
mostatic expansion valve (TXV) regulates refrigerant flow
to control oil temperature entering the bearings. There is al-
ways a flow of refrigerant bypassing the TXV. The bulb for
the expansion valve is strapped to the oil supply line leaving
the heat exchanger and the valve is set to maintain 110 F
(43 C).

NOTE: The expansion valve is not adjustable. Oil sump tem-
perature may be at a lower temperature.
FA Compressors: The oil cooler is a water cooled, tube-in-
shell type heat exchanger. A plug valve is manually set to
maintain proper temperatures. Set the valve to maintain
145 F (63 C) oil sump temperatures while the compressor is
running.

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 alarm is displayed, prevent-
ing the machine from starting. The operator must reset the
alarm at the LID in order to override the starts counter and
start the machine. If Automatic Restart After a Power Fail-
ure is not activated when a power failure occurs, and the
remote contact 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

terminal strip TB5, 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 open-
ing of any contact will result in a safety shutdown and LID
display. Refer to the certified drawings for safety contact
ratings.

Analog temperature sensors may also be added to the op-

tions modules, if installed. These may be programmed to cause
an alert on the CCN network, but will not shut the machine
down.

Spare Alarm Contacts —

Two spare sets of alarm con-

tacts are provided within the starter. The contact ratings are
provided in the certified drawings. The contacts are located
on terminal strip TB6, terminals 5A and 5B, and terminals
5C and 5D.