Carrier 19XRV Specifications download pdf (Page 95)

3. Transfer remaining refrigerant.

a. Close valve 3.

b. Open valve 2.

c. Turn on pumpout condenser water.

d. Run the pumpout compressor until the storage tank

pressure reaches 5 psig (34 kPa), 18 in. Hg vacuum

(41 kPa absolute) in Manual or Automatic mode.

e. Turn off the pumpout compressor.

f. Close valves 1a, 1b, 2, 5, and 6.

g. Turn off pumpout condenser water.

4. Drain the contaminants from the bottom of the storage

tank into a container. Dispose of contaminants safely.

GENERAL MAINTENANCE

Refrigerant Properties —

The standard refrigerant for

the 19XR chiller is HFC-134a. At normal atmospheric pres-

sure, HFC-134a will boil at –14 F (–25 C) and must, therefore,

be kept in pressurized containers or storage tanks. The refriger-

ant is practically odorless when mixed with air and is noncom-

bustible at atmospheric pressure. Read the Material Safety

Data Sheet and the latest ASHRAE Safety Guide for Mechani-

cal Refrigeration to learn more about safe handling of this

refrigerant.

Adding Refrigerant — Follow the procedures de-

scribed in Trim Refrigerant Charge section, page 96.

Adjusting the Refrigerant Charge — If the addi-

tion or removal of refrigerant is required to improve chiller per-

formance, follow the procedures given under the Trim Refrig-

erant Charge section, page 96.

Refrigerant Leak Testing — Because HFC-134a is

above atmospheric pressure at room temperature, leak testing

can be performed with refrigerant in the chiller. Use an elec-

tronic halogen leak detector, soap bubble solution, or ultrasonic

leak detector. Ensure that the room is well ventilated and free

from concentration of refrigerant to keep false readings to a

minimum. Before making any necessary repairs to a leak,

transfer all refrigerant from the leaking vessel.

Leak Rate — It is recommended by ASHRAE that chillers

be taken off line immediately and repaired if the refrigerant

leak rate for the entire chiller is more than 10% of the operating

refrigerant charge per year.

In addition, Carrier recommends that leaks totalling less

than the above rate but more than a rate of 0.1% of the total

charge per year should be repaired during annual maintenance

or whenever the refrigerant is transferred for other service

work.

Test After Service, Repair, or Major Leak — If

all the refrigerant has been lost or if the chiller has been opened

for service, the chiller or the affected vessels must be pressure

tested and leak tested. Refer to the Leak Test Chiller section to

perform a leak test.

TESTING WITH REFRIGERANT TRACER — Use an en-

vironmentally acceptable refrigerant as a tracer for leak test

procedures. Use dry nitrogen to raise the machine pressure to

leak testing levels.

TESTING WITHOUT REFRIGERANT TRACER — An-

other method of leak testing is to pressurize with nitrogen only

and to use a soap bubble solution or an ultrasonic leak detector

to determine if leaks are present.

TO PRESSURIZE WITH DRY NITROGEN

NOTE: Pressurizing with dry nitrogen for leak testing should

not be done if the full refrigerant charge is in the vessel

because purging the nitrogen is very difficult.

1. Connect a copper tube from the pressure regulator on the

cylinder to the refrigerant charging valve. Never apply

full cylinder pressure to the pressurizing line. Follow the

listed sequence.

2. Open the charging valve fully.

3. Slowly open the cylinder regulating valve.

4. Observe the pressure gage on the chiller and close the

regulating valve when the pressure reaches test level. Do

not exceed 140 psig (965 kPa).

5. Close the charging valve on the chiller. Remove the cop-

per tube if it is no longer required.

Repair the Leak, Retest, and Apply Standing

Vacuum Test — After pressurizing the chiller, test for

leaks with an electronic halide leak detector, soap bubble solu-

tion, or an ultrasonic leak detector. Bring the chiller back to at-

mospheric pressure, repair any leaks found, and retest.

After retesting and finding no leaks, apply a standing vacu-

um test. Then dehydrate the chiller. Refer to the Standing Vacu-

um Test and Chiller Dehydration section (page 69) in the Be-

fore Initial Start-Up section.

Checking Guide Vane Linkage — When the chiller

is off, the guide vanes are closed and the actuator mechanism is

in the position shown in Fig. 49. Slack in the guide vane actua-

tor’s drive chain can only be removed with the guide vane

actuator fully closed and the chiller shut down. Complete the

following steps to adjust chain tension and position:

1. Remove the two set screws in the guide vane actuator

sprocket.

2. Loosen the guide vane actuator’s holddown bolts.

3. Pull the guide vane actuator away from the suction hous-

ing along the slotted holes in the actuator bracket.

VALVE 1a1b2345671011

CONDITION C C C C

VALVE 1a1b2345671011

CONDITION CCCCCCCCC

DANGER

HFC-134a will dissolve oil and some nonmetallic materi-

als, dry the skin, and, in heavy concentrations, may dis-

place enough oxygen to cause asphyxiation. When

handling this refrigerant, protect the hands and eyes and

avoid breathing fumes.

CAUTION

Always use the compressor pumpdown function in the

Control Test table to turn on the cooler pump and lock out

the compressor when transferring refrigerant. Liquid refrig-

erant may flash into a gas and cause possible freeze-up

when the chiller pressure is below 30 psig (207 kPa) for

HFC-134a.

WARNING

HFC-134a should not be mixed with air or oxygen and

pressurized for leak testing. In general, this refrigerant

should not be present with high concentrations of air or

oxygen above atmospheric pressures, because the mixture

can undergo combustion.

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Carrier 19XRV Specifications Page 95

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