Adding Refrigerant; Adjusting The Refrigerant Charge; Refrigerant Leak Testing; Leak Rate - Carrier AquaEdge 19XR Start-Up, Operation And Maintenance Instructions Manual

(–25°C) and must, therefore, be kept in pressurized contain-
ers 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 materi-
als, 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

Follow the procedures described in Trim Refrigerant Charge
section, page 39.
CAUTION
Always use the compressor pumpdown function in the
PUMPDOWN/LOCKOUT feature to turn on the cooler
pump and lock out the compressor when transferring refrig-
erant. Liquid refrigerant may flash into a gas and cause pos-
sible freeze-up when the chiller pressure is below 30 psig
(207 kPa) for HFC-134a.

Adjusting the Refrigerant Charge

If the addition or removal of refrigerant is required to improve
chiller performance, follow the procedures given under the
Trim Refrigerant Charge section, page 39.

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 electronic halogen leak detector, soap bub-
ble 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 neces-
sary 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 en-
tire chiller is more than 10% of the operating refrigerant charge
per year.
In addition, Carrier recommends that leaks totaling 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 on page 16 to perform a leak test.
WARNING
HFC-134a should not be mixed with air or oxygen and pres-
surized 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.
DANGER
TESTING WITH REFRIGERANT TRACER
Use an environmentally 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
Another method of leak testing is to pressurize with nitrogen
only and to use a soap bubble solution or an ultrasonic leak de-
tector 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 be-
cause 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 reg-
ulating 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 sections (pages 16 and 18) in the
Before Initial Start-Up section.

Checking Guide Vanes

During normal shutdown, when the chiller is off, the guide
vanes are closed. Check that the coupling is tight on the shaft
and make sure that the guide vane shaft is closed. Complete the
following steps to adjust position (see Fig. 29-31):
1. Remove the set screw in the guide vane coupling.
2. Loosen the holddown bolts on the guide vane actuator.
3. Pull the guide vane actuator away from the suction housing.
4. If required, rotate the guide vane sprocket fully clockwise
and spot-drill the guide vane actuator shaft. Spot-drilling
is necessary when the guide vane actuator sprocket set
screws on the guide vane actuator shaft need to be re-
seated. (Remember: Spot-drill and tighten the first set
screw before spot-drilling for the second set screw.)
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