General Maintenance - Carrier 19EF Series Start Up & Operation Manual

GENERAL MAINTENANCE

Refrigerant Properties —
refrigerant in the 19EF. At normal atmospheric pressure, HFC-
134a will boil at −41 F (−25 C) and therefore must be kept
in pressurized containers or storage tanks. The refrigerants
is practically odorless when mixed with air. This refrigerant
are non-combustible at atmospheric pressure. Read the Ma-
terial Safety Data Sheet and the latest ASHRAE Safety Guide
for Mechanical Refrigeration to learn more about safe han-
dling of this refrigerant.
HFC-134a will dissolve oil and some non-metallic ma-
terials, dry the skin, and, in heavy concentrations, may
displace enough oxygen to cause asphyxiation. In han-
dling this refrigerant, protect the hands and eyes and avoid
breathing fumes.
Adding Refrigerant —
scribed in Charge Refrigerant Into Machine section, page 44.
Always use the compressor pumpdown function in the
Control Test table to turn on the evaporator pump and
lock out the compressor when transferring refrigerant.
Liquid refrigerant may flash into a gas and cause pos-
sible freeze-up when the machine pressure is below
30 psig (207 kPa) for HFC-134a.
Removing Refrigerant —
must be transferred to a storage vessel. Follow the appro-
priate procedures when removing refrigerant.
Adjusting the Refrigerant Charge —
tion or removal of refrigerant is required for improved ma-
chine 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 machine. Use
an electronic detector, soap bubble solution, or ultra-sonic
leak detector. Be sure 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 liquid and gas from the leaking
vessel.
Refrigerant Leak Rate —
machines should be immediately taken off line and repaired
if the refrigerant leakage rate for the entire machine 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 should be repaired during annual maintenance or when-
ever the refrigerant is pumped over for other service work.
Test After Service, Repair, or Major Leak —
all refrigerant has been lost or if the machine has been opened
for service, the machine or the affected vessels must be pres-
surized and leak tested. Refer to the Leak Test Machine sec-
tion to perform a leak test.
HFC-134a should not be mixed with air or oxygen and
pressurized for leak testing. In general, this refrigerant
should not be allowed to be present with high concen-
trations of air or oxygen above atmospheric pressures,
as the mixture can undergo combustion.
HFC-134a is the standard
Follow the proedures de-
The 19EF refrigerant charge
If the addi-
Because HFC-134a is
ASHRAE recommends that
If
REFRIGERANT TRACER — Use an environmentally ac-
ceptable 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 use a soap bubble solution or an ultrasonic leak detector
to determine if leaks are present. This 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 machine 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 machine. Remove the
copper tube if no longer required.
Repair the Leak, Retest, and Apply Standing
Vacuum Test —
After pressurizing the machine, test for
leaks with an electronic leak detector, soap bubble solution,
or an ultrasonic leak detector. Bring the machine back to at-
mospheric pressure, repair any leaks found, and restest.
After retesting and finding no leaks, apply a standing vacuum
test, and then dehydrate the machine. Refer to the Standing
Vacuum Test and Machine Dehydration in the Before Initial
Start-Up section, page 37.
Checking Guide Vane Linkage —
chine is off, the guide vanes are closed and the actuator mecha-
nism is in the position shown in Fig. 28. If slack develops in
the drive chain, backlash can be eliminated as follows:
1. With the machine 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. Make
sure that the guide vane shaft is rotated fully in the clock-
wise direction in order for it to be fully closed.
Trim Refrigerant Charge —
to adjust the refrigerant charge to obtain optional machine
performance, operate the machine at design load and then
add or remove refrigerant slowly until the difference be-
tween leaving chilled water temperature and the cooler re-
frigerant temperature reaches design conditions or becomes
a minimum. Do not overcharge.
WEEKLY MAINTENANCE
Check the Lubrication System —
on the reservoir sight glass, and observe the level each week
while the machine is shut down.
If the level goes below the lower sight glass, the oil re-
claim system will need to be checked for proper operation.
If additional oil is required, add it through the oil drain charg-
ing valve (Fig. 2). A pump is required for adding oil against
refrigerant pressure. The oil charge is approximately 15 gal-
lons (57 L) for compressors. The added oil must meet Car-
rier specifications for the 19EF. Refer to Change Oil and Oil
Filter and Oil Changes sections. Any additional oil that is
added should be logged by noting the amount and date. Any
oil that is added due to oil loss that is not related to service
will eventually return to the sump. It must be removed when
the level is high.
50
When the ma-
If it becomes necessary
Mark the oil level
1196