Leak Test Chiller; Standing Vacuum Test - Carrier 19XRV Start-Up, Operation And Maintenance Instructions Manual

Leak Test Chiller
-- Due to regulations regarding refiig-
erant emissions and the difficulties associated with separating
contaminants from the refrigerant, Carrier recommends the
following leak test procedure. See Fig. 29 for an outline of the
leak test procedure. Refer to Fig. 30 and 31 during pumpout
procedures and Tables 11A and 11B for refi'igerant pressure/
temperature values.
1. [f the pressure readings are normal for the chiller
condition:
a. Evacuate the holding charge fiom the vessels, if
present.
b. Raise the chiller pressure, if necessary, by adding
refrigerant until pressure is at the equivalent satu-
rated pressure for the surrounding temperature.
Follow the pumpout procedures in the Transfer
Refrigerant from Pumpout Storage Tank to Chiller
section, Steps I a - e, page 72.
Never charge liquid refrigerant into the chiller if the pres-
sure in the chiller is less than 35 psig (241 kPa) for
HFC-134a. Charge as a gas only, with the cooler and
condenser pumps running, until this pressure is reached,
using PUMPDOWN LOCKOUT and TERMINATE
LOCKOUT mode on the PIC III. Flashing of liquid
lefrigerant at low pressures can cause tube freeze-up and
considerable damage.
c. Leak test chiller as outlined in Steps 3-9.
2. If the pressure readings are abnormal for the chiller
condition:
a. Prepare to leak test chillers shipped with refriger-
ant (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 that 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 possible, given the fact that small leaks may be
present in the system. This can be accomplished by
following the dehydration procedure, outlined in
the Chiller Dehydration section, page 58.
h. Slowly raise the system pressure to a maximum of
160 psig (1103 kPa) but no less than 35 psig
(241 kPa) for HFC-134a by adding refrigerant.
Proceed with the test for small leaks (Steps 3-9).
3. Check the chiller carefully with an electronic leak detec-
tol: halide torch, or soap bubble solution.
4. Leak Determination --If an electronic leak detector
indicates a leak, use a soap bubble solution, if possible, to
confirm. Total all leak rates for the entire chillel: Leakage
at rates greater than 0.1% of the total charge per year must
be repaired. Note the toted chiller leak rate on the start-up
_eport.
5. If no leak is found during the initi_d start-up procedures,
complete the transfer of refrigerant gas from the pumpout
storage tank to the chiller (see Transfer Refiigerant from
Pumpout Storage Tank to Chiller section, page 72).
Retest for leaks.
6. If no leak is found after a retest:
a. Transfer the refrigerant to the pumpout storage
tank and perform a standing vacuum test as
outlined in the Standing Vacuum Test section,
below.
b. If the chiller fails the standing vacuum test, check
for large leaks (Step 2b).
c. If the chiller passes the standing vacuum test,
dehydrate the chiller. Follow the procedure in
the Chiller Dehydration section. Charge the chiller
with refrigerant (see Transfer Refrigerant fiom
Pumpout Storage Tank to Chiller section,
page 72).
7. If a leak is found after a retest, pump the refrigerant back
into the pumpout storage tank or, if isolation valves are
present, pump the refrigerant into the non-leaking
vessel (see Pumpout and Refrigerant Transfer procedures
section).
8. Transfer the refrigerant until the chiller pressure is at
18 in. Hg (40 kPa absolute).
9. Repair the leak and repeat the procedure, beginning from
Step 2h, to ensure a leak-tight repail: (If the chiller is
opened to the atmosphere for an extended period, evacu-
ate it before repeating the leak test.)
Standing Vacuum Test
--
When perforlning the stand-
ing vacuum test or chiller dehydi'ation, use a manometer or a
wet bulb indicatol: 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
indicator to the chillel:
2. Evacuate the vessel (see Pumpout and Refrigerant
Transfer Procedures section, page 71 ) to at least 18 in. Hg
vac, ref 30-in. bar (41 kPa), using a vacuum pump or the
pump out 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 (0.17 kPa) in
24 hours, the chiller is sufficiently tight.
b. ffthe leakage rate exceeds 0.05 in. Hg (0.17 kPa) in
24 hours, repressurize the vessel and test for leaks.
If refrigerant is available in the other vessel, pressur-
ize by following Steps 2-10 of Return Chiller To
Normal Operating Conditions section, page 73. If
not, use nitrogen and a refi'igerant tracer Raise the
vessel plessure in increments until the leak is
detected. If refrigerant is used, the maximum gas
pressure is approximately 70 psig (483 kPa) for
HFC-134a at normal ambient temperature. If nitro-
gen is used, limit the leak test pressure to 160 psig
(1103 kPa) maximum.
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