12
Leak Check
When all refrigeration line connections have been made, the complete system, including factory
connections, should be leak checked. Failure to do so may waive factory warranty. Remove the low
pressure transducer before pressurizing for leak check.
Charge the system 300 PSIG with dry-
nitrogen and check each joint and connection with soap bubble for leak. Install the pressure transducer
back after the pressure is released.
Evacuation, Dehydration and Start-Up
A vacuum of 500 microns or less must be pulled to properly dehydrate the system. This requires a two-
stage vacuum pump with an electronic vacuum indicator. The vacuum level has to be maintained to be
sure no moisture is inside the oil.
CAUTION: Do not operate the compressor while the system is in a vacuum. This will waive factory
warranty for Scroll compressor.
Evacuation Procedure
A. Open all condensing unit service valves and relieve system pressure. Also, open any line valves
installed in the system and energize all solenoid valves to facilitate evacuation.
B. Connect the vacuum pump to the high and low sides of the system using 1/4” or larger copper lines
or 1/4” ID hoses with high vacuum designation.
C. Leaks or moisture will be indicated if the system pressure rises when the vacuum line is closed off.
D. A final vacuum of 500 microns should be pulled and maintained before charging. Charge
the high side until the system pressure is equal to the pressure in the refrigerant cylinder.
Charging Procedure
A. Preliminary
1. Calculate the preliminary refrigerant charge using the following Formula:
Preliminary Charge = (Rated Tons of Refrigeration x 3 lbs of R-449A) + (Liquid Line Refrigerant
Weight)
Rated Tons for various compressors in MAC-7-8 are given below in Table 4.
Table 4
Compressor
Capacity
(Tons) Evap Temp (
F)
ZF13K4E-TF5 1.15 -20
ZF15K4E-TF5 1.47 -20
ZF18K4E-TF5 1.79 -20
ZS11KAE-TF5
1.09 25
NOTE: For Liquid Line Refrigerant Weight, Reference Table 5 Below
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