General Maintenance - Carrier 23xl Start-Up, Operation And Maintenance Instructions Manual

GENERAL MAINTENANCE

Refrigerant Properties —
are the standard refrigerants in the 23XL. At normal atmo-
spheric pressure, HCFC-22 will boil at –41 F (–40.5 C) and
HFC-134a will boil at –14 F (–25 C), and must, therefore, be
kept in pressurized containers or storage tanks. The refrigerants
are practically odorless when mixed with air. Both refrigerants
are non-combustible at atmospheric pressure. Read the Materi-
al Safety Data Sheet and the latest ASHRAE Safety Guide for
Mechanical Refrigeration to learn more about safe handling of
these refrigerants.
HCFC-22 and HFC-134a will dissolve oil and some non-
metallic materials, dry the skin, and, in heavy concentra-
tions, may displace enough oxygen to cause asphyxiation.
In handling this refrigerant, protect the hands and eyes and
avoid breathing fumes.
Adding Refrigerant —
in the Charge Refrigerant into Chiller section, page 64.
Always use the compressor pumpdown function in the
Control Test mode to turn on the evaporator pump and lock
out the compressor when transferring refrigerant. Liquid
refrigerant may flash into a gas and cause possible freeze-
up when the chiller pressure is below 65 psig (448 kPa)
[30 psig (207 kPa)].
Removing Refrigerant —
tem is used, the 23XL refrigerant charge may be transferred to
a storage vessel or within the condenser or cooler if isolation
valves are present. Follow procedures in the Pumpout and Re-
frigerant Transfer Procedures section when removing refriger-
ant from the storage tank to the chiller.
Adjusting the Refrigerant Charge —
tion or removal of refrigerant is required for improved chiller
performance, follow the procedures given under the Trim Re-
frigerant Charge section, on this page.
Refrigerant Leak Testing —
HFC-134a are above atmospheric pressure at room tempera-
ture, leak testing can be performed with refrigerant in the chill-
er. Use an electronic leak detector, halide leak detector, soap
bubble solution, or ultra-sonic leak detector. Be sure that the
room is well ventilated and free from concentration of refriger-
ant to keep false readings to a minimum. Before making any
necessary repairs to a leak, transfer all refrigerant from the
leaking vessel.
Refrigerant Leak Rate —
chillers should be immediately taken off line and repaired if the
refrigerant leakage rate for the entire chiller is more than 10%
of the operating refrigerant charge per year.
Additionally, Carrier recommends that leaks totalling less
than the above rate but more than a rate of 1 lb (0.5 kg) per year
HCFC-22 and HFC-134a
Follow the procedures described
If the optional pumpout sys-
If the addi-
Because HCFC-22 and
ASHRAE recommends that
should be repaired during annual maintenance or whenever the
refrigerant is pumped over for other service work.
Test After Service, Repair, or Major Leak —
all refrigerant has been lost or if the chiller has been opened for
service, the chiller or the affected vessels must be pressured
and leak tested. Refer to the Leak Test Chiller section to per-
form a leak test.
HCFC-22 and HFC-134a will dissolve oil and some non-
metallic materials, dry the skin, and, in heavy concentra-
tions, may displace enough oxygen to cause asphyxiation.
In handling this refrigerant, protect the hands and eyes and
avoid breathing fumes.
REFRIGERANT TRACER — Use an environmentally ac-
ceptable refrigerant as a tracer for leak test procedures.
TO PRESSURIZE WITH DRY NITROGEN — Anoth-
er method of leak testing is to pressure with nitrogen only and
use soap bubble solution or an ultrasonic leak detector to deter-
mine if leaks are present. This should only be done if all refrig-
erant has been evacuated from the vessel.
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
copper tube if no longer required.
Repair the Refrigerant Leak, Retest, and
Apply Standing Vacuum Test —
the chiller, test for leaks with a soap bubble solution, an elec-
tronic leak detector, a halide torch, or an ultrasonic leak detec-
tor. Bring the chiller back to atmospheric 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 Chiller Dehy-
dration in the Before Initial Start-Up section, page 58.
Trim Refrigerant Charge —
to adjust the refrigerant charge to obtain optimum chiller per-
formance, operate the chiller at design load and then add or re-
move refrigerant slowly until the difference between leaving
chilled water temperature and the cooler refrigerant tempera-
ture reaches design conditions. Do not overcharge. For super-
heat information, see the Troubleshooting section on page 76.
Refrigerant may be added either through the optional stor-
age tank or directly into the chiller as described in the section
entitled, Refrigerant Charging.
To remove any excess refrigerant, follow the procedure in
Transfer Refrigerant from Chiller to Pumpout Storage Tank
section, Steps 1a, b on page 71.
72
If
After pressurizing
If it becomes necessary