Reznor MASA Unit Installation Manual - Manual (Page 17)

Form I-COND, P/N 220746R6, Page 17
pressurized. If circuit is not pressurized, the nitrogen has escaped. Recharge
with dry nitrogen to 150 psi. (Maximum test pressure is 450 psi.) Use soap
bubbles or other leak-detecting method. Repair as needed to ensure a leak-
free circuit in the condensing unit. Repeat with Circuit B.
NOTE: The nitrogen charge in the condensing unit circuits may be used during
the brazing process as part of the purge. See Paragraph 6.1.3.6.
6.2.2 Leak Test the
Field-Installed Piping
Pressurize one of the circuits with dry nitrogen to 150 psi. (Maximum test pres-
sure is 450 psi.) Test for leaks. Repair as needed to ensure a leak-free circuit.
When the circuit is successfully leak tested, allow the nitrogen to escape to the
atmosphere through the pump port on the gauge manifold. Repeat with the
second circuit.
TABLE 6 - Condenser
Refrigerant Charge
by Weight and Line
Charge per Size and
Length of Liquid Line
MASA Size Circuit 60 90 120 150 180 240
Condenser
Refrigerant
Charge (lbs)
A 5.0 6.0 6.3 9.6 8.6 11.0
B 5.9 9.0 9.5 11.2 11.3 14.8
PLUS lbs listed below of R-410A refrigerant per each 50 feet (15.2M)
actual length of liquid line by tubing size
Liquid Line
Tubing Size (OD)
Lbs of R-410A Refrigerant (saturated liquid @
77°F/25°C) per each 50 ft (15.2M) of Liquid Line
1/2 3.4
5/8 5.4
3/4 8.0
6.3 Evacuate the
Circuits
Evacuate one circuit at a time. Use a vacuum pump and micron gauge. Each
circuit must be evacuated to hold a 500 micron vacuum. Vacuum must be
pulled on both the discharge (high) and suction (low) side. Do the suction
side first; and the compressor discharge side second. To establish that a cir-
cuit is leak-free and moisture-free, a standing vacuum test is recommended.
Close off the valve to the vacuum pump and observe the micron gauge. If the
vacuum gauge does not rise above 500 microns in one minute, the evacua-
tion should be complete. If vacuum gauge does rise above 500 microns in one
minute, evacuation is incomplete or the system has a leak. Repeat as needed
until evacuation is complete. The evacuation process must be done on each
circuit.
NOTE: Evacuation will not remove moisture from POE oil. Moisture must be
prevented from getting in the oil.
6.4 Charge with R-
410A Refrigerant
Use only R-410A refrigerant.
NOTE: Outdoor temperature must be between 70-95°F (21-35°C) for verifying
superheat and subcooling. If temperature is not within this range, consult the
factory service department before charging.
If equipped with an optional hot gas bypass, disable the hot gas bypass valve
before charging. Remove cap and backoff spring tension until valve is dis-
abled. ( NOTE: See Paragraph 8.3.3 to reset.)
Estimate the refrigerant charge for each circuit. TABLE 6 lists the weight of
refrigerant required for each condenser (condenser coil and receiver) plus the
amount per foot depending on size and length of the liquid line.
Charge the refrigerant slowly through the gauge port on the liquid line.
R-410A refrigerant must be charged as a liquid. R-410A cylinders are rose
colored (pink) and have a dip tube for charging liquid from an upright position.