General Maintenance - Carrier 19XR Start-Up, Operation And Maintenance Instructions Manual

GENERAL MAINTENANCE

Refrigerant Properties —
the 19XR chiller is HFC-134a. At normal atmospheric pres-
sure, HFC-134a will boil at –14 F (–25 C) and must, there-
fore, be kept in pressurized containers or storage tanks. The
refrigerant is practically odorless when mixed with air
and is noncombustible at atmospheric pressure. Read the
Material Safety Data Sheet and the latest ASHRAE Safety
Guide for Mechanical Refrigeration to learn more about safe
handling of this refrigerant.
HFC-134a will dissolve oil and some nonmetallic ma-
terials, dry the skin, and, in heavy concentrations, may
displace enough oxygen to cause asphyxiation. When
handling this refrigerant, protect the hands and eyes and
avoid breathing fumes.
Adding Refrigerant —
scribed in Trim Refrigerant Charge section, this page.
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. Liq-
uid refrigerant may flash into a gas and cause possible
freeze-up when the chiller pressure is below
30 psig (207 kPa) for HFC-134a.
Removing Refrigerant —
tem is used, the 19XR refrigerant charge may be transferred
to a pumpout storage tank or to the chiller condenser or cooler
vessels. Follow the procedures in the Pumpout and Refrig-
erant Transfer Procedures section when transferring refrig-
erant from one vessel to another.
Adjusting the Refrigerant Charge —
tion or removal of refrigerant is required to improve chiller
performance, follow the procedures given under the Trim
Refrigerant Charge section, this page.
Refrigerant Leak Testing —
above atmospheric pressure at room temperature, leak test-
ing can be performed with refrigerant in the chiller. Use an
electronic halide leak detector, soap bubble solution, or ultra-
sonic leak detector. Ensure that the room is well ventilated
and free from concentration of refrigerant to keep false read-
ings to a minimum. Before making any necessary repairs to
a leak, transfer all refrigerant from the leaking vessel.
Leak Rate —
It is recommended byASHRAE that chill-
ers be taken off line immediately and repaired if the refrig-
erant 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 mainte-
nance or whenever the refrigerant is transferred for other serv-
ice work.
Test After Service, Repair, or Major Leak —
all the refrigerant has been lost or if the chiller has been opened
for service, the chiller or the affected vessels must be pres-
sure tested and leak tested. Refer to the Leak Test Chiller
section to perform a leak test.
The standard refrigerant for
Follow the procedures de-
If the optional pumpout sys-
If the addi-
Because HFC-134a is
If
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 mix-
ture can undergo combustion.
REFRIGERANT TRACER — Use an environmentally
acceptable refrigerant as a tracer for leak test procedures.
TO PRESSURIZE WITH DRY NITROGEN — Another
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.
NOTE: Pressurizing with dry nitrogen for leak testing should
only be done if all refrigerant 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 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
solution, or an ultrasonic leak detector. Bring the chiller back
to atmospheric pressure, repair any leaks found, and retest.
After retesting and finding no leaks, apply a standing vacuum
test. Then dehydrate the chiller. Refer to the Standing Vacuum
Test and Chiller Dehydration section (pages 48 and 51) in
the Before Initial Start-Up section.
Checking Guide Vane Linkage —
chiller is off, the guide vanes are closed and the actuator
mechanism is in the position shown in Fig. 33. If slack de-
velops in the drive chain, do the following to eliminate
backlash:
1. With the chiller shut down and the actuator fully closed,
remove the chain guard and loosen the actuator bracket
holddown bolts.
2. Loosen guide vane sprocket adjusting bolts.
3. Pry bracket upwards to remove slack, then retighten the
bracket holddown bolts.
4. Retighten the guide vane sprocket adjusting bolts. En-
sure that the guide vane shaft is rotated fully in the clock-
wise direction in order close it fully.
Trim Refrigerant Charge —
performance, it becomes necessary to adjust the refrigerant
charge, operate the chiller at design load and then add or
remove refrigerant slowly until the difference between the
leaving chilled water temperature and the cooler refrigerant
temperature reaches design conditions or becomes a mini-
mum. Do not overcharge.
Refrigerant may be added either through the storage tank
or directly into the chiller as described in the Charge
Refrigerant into Chiller section.
To remove any excess refrigerant, follow the procedure in
Transfer Refrigerant from Chiller to Pumpout Storage Tank
section, Steps 1a and b, page 63.
65
When the
If, to obtain optimal chiller