Carrier 23XL Specifications download pdf (Page 55)

Table 8 — Control Test Table Functions

TESTS TO BE PERFORMED DEVICES TESTED

1. Automated Tests* Operates the second through seventh tests

2. PSIO Thermistors Entering chilled water

Leaving chilled water

Entering condenser water

Leaving condenser water

Discharge temperature

Motor winding temperature

Oil sump temperature

3. Option Module Thermistors Common chilled water supply sensor

Common chilled water return sensor

Remote reset sensor

Temperature sensor — Spare 1

Spare 2

Spare 3

Spare 4

Spare 5

Spare 6

Spare 7

Spare 8

Spare 9

4. Transducers Evaporator pressure

Condenser pressure

Oil pressure

Oil pressure differential

5. Slide Valve Assembly Load (Close

Unload (Open)

6. Pumps Either or both pumps may be

activated:

Chilled water pump — Conﬁrm ﬂow

Condenser water pump — Conﬁrm ﬂow

7. Discrete Outputs All outputs or individual outputs may be

energized:

Hot gas bypass relay

Oil heater relay (Frame 1 and 2 Machines)

VI inlet relay

Tower fan relay

Alarm relay

8. Pumpdown When using pumpdown lockout,

observe freeze-up precautions when

removing charge:

Instructs operator as to which valves to

close and when

Starts chilled water and condenser

water pumps and conﬁrms ﬂow

Monitors — Evaporator pressure

Condenser pressure

Evaporator temperature

during pumpout

procedures

Turns pumps off after pumpdown

Locks out compressor

9. Terminate Lockout Starts pumps and monitors ﬂows

Instructs operator as to which valves to

open and when

Monitors — Evaporator pressure

Condenser pressure

Evaporator temperature

during charging process

Terminates compressor lockout

10. Refrigerant Type† Sets the refrigerant type used:

HCFC-22 or HFC-134a

*During any of the tests that are not automated, an out-of-range reading will

have an asterisk (*) next to the reading and a message will be displayed.

†Make sure to Attach to Local Device after changing refrigerant type. Refer to

Selecting Refrigerant Type section on page 53. See Fig. 21.

Check Optional Pumpout System Controls and

Compressor —

Controls include an on/off switch, a 3-amp

fuse, the compressor overloads, an internal thermostat,

a compressor contactor, and a refrigerant high pressure

cutout. The high pressure cutout is factory set to open at 220

± 5 psig (1250 ± 34 kPa), and automatically reset at 185

+0,-7 (1280 +0,-48 kPa) with HCFC-22. HFC-134a units open

at 161 psig (1110 kPa) and reset at 130 psig (896 kPa). Check

that the water-cooled condenser has been connected. Loosen

the compressor holddown bolts to allow free spring travel.

Open the compressor suction and discharge service valves.

Check that oil is visible in the compressor sight glass. Add

oil if necessary.

See Pumpout and Refrigerant Transfer Procedures

and Optional Pumpout System Maintenance sections on

pages 61 and 67 for details on transfer of refrigerant, oil speci-

ﬁcations, etc.

Charge Refrigerant into Machine

The transfer, addition, or removal of refrigerant in spring

isolated machines may place severe stress on external

piping if springs have not been blocked in both up and

down directions.

The standard 23XL machine will have the refrigerant al-

ready charged in the vessels. The 23XL may be ordered with

a nitrogen holding charge of 15 psig (103 kPa). Evacuate the

entire machine, and charge machine from refrigerant

cylinders.

23XL MACHINE EQUALIZATION WITHOUT

PUMPOUT UNIT

When equalizing refrigerant pressure on the 23XL ma-

chine after service work or during the initial machine

start-up, do not use the discharge isolation valve to equal-

ize. The motor cooling isolation valve should be used as

the equalization valve.

To equalize the pressure differential on a refrigerant iso-

lated 23XL machine, use the TERMINATE LOCKOUT func-

tion of the Control Test from the SERVICE menu. This will

help to turn on pumps and advise the proper procedure. The

following procedure describes how to equalize refrigerant

pressure on an isolated 23XL machine without a pumpout

unit:

1. Access TERMINATE LOCKOUT function on the Con-

trols Test.

2. Turn on the chilled water and condenser water pumps to

ensure against freezing.

3. Slowly open the motor cooling isolation valve 13.

The machine cooler and condenser pressures will gradu-

ally equalize. This process will take approximately

15 minutes.

4. Once the pressures have equalized, the condenser isola-

tion valve and cooler isolation valve may be opened. Re-

fer to Fig. 31-34, Valves 11 and 12.

Whenever turning the discharge isolation valve, be sure

to re-attach the valve locking device. This will prevent

the valve from opening or closing during service work

or during machine operation.

The full refrigerant charge on the 23XL will vary with

machine components and design conditions, indicated on the

job data speciﬁcations. An approximate charge may be found

in Table 9.

Always operate the condenser and chilled water pumps

during charging operations to prevent freeze-ups. Use the

Control Test, Terminate Lockout to monitor conditions and

start the pumps.

If the machine has been shipped with a holding charge,

the refrigerant will be added through the refrigerant charg-

ing valve (Fig. 31-34) or to the pumpout charging connec-

tion. First evacuate the nitrogen holding charge from the vessels.

Charge the refrigerant as a gas until the system pressure ex-

ceeds 68 psig (469 kPa) [35 psig (141 kPa)]. After the ma-

chine is beyond this pressure, the refrigerant should be charged

as a liquid until all of the recommended refrigerant charge

has been added.

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Carrier 23XL Specifications Page 55

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