Carrier 19EF Series, Start Up & Operation Manual

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2. If the pressure readings are abnormal for machine
condition:
a. Prepare to leak test machines shipped with refrigerant
(Step 2h).
b. Check for large leaks by connecting a nitrogen bottle
and raising the pressure to 30 psig (207 kPa). Soap
test all joints. If the test pressure holds for 30 minutes,
prepare the test for small leaks (Steps 2g - h).
c. Plainly mark any leaks which are found.
d. Release the pressure in the system.
e. Repair all leaks.
f. Retest the joints that were repaired.
g. After successfully completing the test for large leaks,
remove as much nitrogen, air, and moisture as pos-
sible, given the fact that small leaks may be present in
the system. This can be accomplished by following
the dehydration procedure, outlined in the Machine De-
hydration section, this page.
h. Slowly raise the system pressure to maximum
210 psig (1448 kPa) but no less than 35 psig
(241 kPa) by adding refrigerant. Proceed with the test
for small leaks (Steps 3-9).
3. Check the machine carefully with an electronic leak de-
tector, halide torch, or soap bubble solution.
4. Leak Determination — If an electronic leak detector in-
dicates a leak, use a soap bubble solution, if possible, to
confirm. Total all leak rates for the entire machine. Leak-
age at rates greater than 1 lb/year (0.45 kg/year) for the
entire machine must be repaired. Note total machine leak
rate on the start-up report.
5. If no leak is found during initial start-up procedures, com-
plete the transfer of refrigerant gas from the storage tank
to the machine (see Refrigerant Transfer Procedure).
Retest.
6. If no leak is found after a retest:
a. Transfer the refrigerant and perform a standing vacuum
test as outlined in the Standing Vacuum Test section,
this page.
b. If the machine fails this test, check for large leaks
(Step 2b).
c. Dehydrate the machine if it passes the standing vacuum
test. Follow the procedure in the Machine Dehydra-
tion section. Charge machine with refrigerant (see Re-
frigerant Transfer Procedure).
7. If a leak is found, transfer the refrigerant out of the
machine (see Refrigerant Transfer Procedure section on
page 48).
8. Transfer the refrigerant until machine pressure is at
18 in. Hg (41 kPa absolute).
9. Repair the leak and repeat the procedure, beginning from
Step 2h to ensure a leaktight repair. (If machine is opened
to the atmosphere for an extended period, evacuate it be-
fore repeating leak test.)
Standing Vacuum Test —
When performing the stand-
ing vacuum test, or machine dehydration, use a manometer
or a wet bulb indicator. Dial gages cannot indicate the small
amount of acceptable leakage during a short period of time.
1. Attach an absolute pressure manometer or wet bulb in-
dicator to the machine.
2. Evacuate the vessel (using the same procedure shown in
Refrigerant Transfer Procedure section, page 48) to at least
18 in. Hg vac, ref 30-in. bar (41 kPa absolute), using a
vacuum pump or the pumpout unit.
3. Valve off the pump to hold the vacuum and record the
manometer or indicator reading.
4. a. If the leakage rate is less than 0.05 in. Hg (.17 kPa) in
24 hours, the machine is sufficiently tight.
b. If the leakage rate exceeds 0.05 in. Hg (.17 kPa) in 24
hours, repressurize the vessel and test for leaks. Refer
the leak test procedures in Fig. 24. Raise the vessel
pressure in increments until the leak is detected. If re-
frigerant is used, the maximum gas pressure is ap-
proximately 70 psig (483 kPa) at normal ambient
temperature. If nitrogen is used, limit the leak test pres-
sure to 230 psig (1585 kPa) maximum.
5. Repair leak, retest, and proceed with dehydration.
Machine Dehydration —
Dehydration is recom-
mended if the machine has been open for a considerable pe-
riod of time, if the machine is known to contain moisture, or
if there has been a complete loss of machine holding charge
or refrigerant pressure.
Do not start or megohm test the compressor motor or
oil pump motor, even for a rotation check, if the ma-
chine is under dehydration vacuum. Insulation break-
down and severe damage may result.
Dehydration is readily accomplished at room tempera-
tures. Use of a cold trap (Fig. 25) may substantially reduce
the time required to complete the dehydration. The higher
the room temperature, the faster dehydration takes place. At
low room temperatures, a very deep vacuum is required for
boiling off any moisture. If low ambient temperatures are
involved, contact a qualified service representative for the
dehydration techniques required.
Perform dehydration as follows:
1. Connect a high capacity vacuum pump (5 cfm
[.002 m
3
/s] or larger is recommended) to the refrigerant
charging valve (Fig. 5). Tubing from the pump to the ma-
chine should be as short and as large a diameter as pos-
sible to provide least resistance to gas flow.
2. Use an absolute pressure manometer or a wet bulb vacuum
indicator to measure the vacuum. Open the shutoff valve
to the vacuum indicator only when taking a reading. Leave
the valve open for 3 minutes to allow the indicator vacuum
to equalize with the machine vacuum.
3. Open all isolation valves (if present), if the entire ma-
chine is to be dehydrated.
4. With the machine ambient temperature at 60 F (15.6 C)
or higher, operate the vacuum pump until the manometer
reads 29.8 in. Hg vac, ref 30 in. bar. (0.1 psia)
(–100.61 kPa) or a vacuum indicator reads 35 F (1.7 C).
Operate the pump an additional 2 hours.
Do not apply greater vacuum than 29.82 in. Hg vac
(757.4 mm Hg) or go below 33 F (.56 C) on the wet bulb
vacuum indicator. At this temperature/pressure, isolated
pockets of moisture can turn into ice. The slow rate of
evaporation (sublimination) of ice at these low temperatures/
pressures greatly increases dehydration time.
5. Valve off the vacuum pump, stop the pump, and record
the instrument reading.
6. After a 2-hour wait, take another instrument reading. If
the reading has not changed, dehydration is complete. If
the reading indicates vacuum loss, repeat Steps 4 and 5.
7. If the reading continues to change after several attempts,
perform a leak test up to the maximum 170 psig
(1172 kPa) pressure. Locate and repair the leak, and re-
peat dehydration.
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