Carrier 23XL Spezifikationen PDF herunterladen (Seite 39)

When the machine is in RECYCLE mode, the chilled wa-

ter pump relay remains energized so that the chilled water

temperature can be monitored for increasing load. The re-

cycle control uses RECYCLE RESTART DELTA T to check

when the compressor should be restarted. RECYCLE RE-

START DELTA T is an operator-conﬁgured function which

defaults to5F(3C).This value is viewed/modiﬁed on the

Service1 screen. The compressor will restart when:

• in LCW CONTROL the LEAVING CHILLED WATER tem-

perature is greater than the CONTROL POINT plus the RE-

CYCLE RESTART DELTA T; or

• in ECW CONTROL, the ENTERING CHILLED WATER

temperature is greater than the CONTROL POINT plus the

RECYCLE RESTART DELTA T

Once these conditions are met, the compressor shall ini-

tiate a start-up, with a normal start-up sequence.

An Alert condition may be generated if 5 or more RE-

CYCLE STARTUPs occur in less than 4 hours. This exces-

sive recycling can reduce machine life. Compressor recycling

due to extremely low loads should be stopped. To stop com-

pressor recycling, use the time schedule to shut the machine

down during low load operation. Increase the machine load

by running the fan systems. If the hot gas bypass is installed,

adjust the values to ensure that hot gas is energized during

light load conditions. Increase the RECYCLE RESTART

DELTA T on the Service1 table. By increasing this value,

the off time of the machine is increased.

The machine should not be operated below design mini-

mum load.

Safety Shutdown — A safety shutdown is identical to

a manual shutdown with the exception that the LID will dis-

play the reason for the shutdown, the alarm light will blink

continuously, the default screen display will freeze, and the

spare alarm contacts will be energized. A safety shutdown

requires that the RESET

softkey be pressed in order to

clear the alarm. Before pressing the RESET

softkey, record

the default screen values. If the alarm is still present, the

alarm light will continue to blink. Once the alarm is cleared,

the operator must press the CCN

or LOCAL softkey to

restart the machine.

Do not reset starter loads or any other starter safety for

30 seconds after the compressor has stopped. Voltage

output to the compressor start signal is maintained for

10 seconds to determine starter fault.

BEFORE INITIAL START-UP

Job Data Required

• list of applicable design temperatures and pressures (prod-

uct data submittal)

• machine certiﬁed drawings

• starting equipment details and wiring diagrams

• diagrams and instructions for special controls or options

• 23XL Installation Instructions

• pumpout unit instructions

Field Supplied Equipment Required

• mechanic’s tools (refrigeration)

• digital volt-ohmmeter (DVM)

• clamp-on ammeter

• electronic leak detector

• absolute pressure manometer or wet-bulb vacuum indica-

tor (Fig. 29)

• 500 v insulation tester (megohmmeter)

Using the Optional Storage Tank and Pumpout

System —

Refer to Pumpout and Refrigerant Transfer Pro-

cedures section for pumpout system preparation, refrigerant

transfer, and machine evacuation.

Remove Shipping Packaging — Remove any pack-

aging material from the control center, power panel, slide

valve assembly, motor temperature sensor cover, and the factory-

mounted starter.

Open Oil Circuit Valves — Check that the oil ﬁlter

isolation valves (Fig. 3 and 4) are open by removing the valve

cap and checking the valve stem.

Check Machine Tightness — Figure 30 outlines the

proper sequence and procedures for leak testing.

23XL machines are shipped with a full refrigerant and oil

charge. Units may be ordered with the refrigerant shipped

separately, and a 15 psig (103 kPa) nitrogen-holding charge

in each vessel. To determine if there are any leaks, the ma-

chine should be charged with refrigerant. Use an electronic

leak detector to check all ﬂanges and solder joints after the

machine is pressurized. If any leaks are detected, follow the

leak test procedure.

If the machine is spring isolated, keep all springs blocked

in both directions to prevent possible piping stress and dam-

age when refrigerant is transferred from vessel to vessel dur-

ing the leak test process or any time refrigerant is transferred.

Adjust the springs when the refrigerant is in operating con-

dition, and the water circuits are full.

Refrigerant Tracer — Carrier recommends the use of

an environmentally acceptable refrigerant tracer for leak test-

ing with an electronic detector or halide torch.

Ultrasonic leak detectors also can be used if the machine

is under pressure.

Do not use air or oxygen as a means of pressurizing the

machine. Some mixtures of HCFC-22 or HFC-134a and

air can undergo combustion.

Fig. 29 — Typical Wet-Bulb Type

Vacuum Indicator

1 2 ... 34 35 36 37 38 39 40 41 42 43 44 ... 103 104

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