Reznor MASA Unit Installation Manual - Manual (Page 25)

Form I-COND, P/N 220746R6, Page 25
9.2.3 Refrigerant
Charge
IMPORTANT
All refrigeration
checks MUST
be made by a
refrigeration
technician
qualified in
R-410A refrigerant.
Equipment and
tools MUST be
designed for
R-410A refrigerant.
PREPARATION:
□
To verify superheat and subcooling, outdoor temperature must be
between 70-95°F (21-35°C). If temperature is not within this range,
consult the factory service department before charging.
□
Operate for 30 minutes for system to stabilize.
□
Check BOTH refrigerant circuit A and circuit B; isolate each cir-
cuit before measuring superheat and subcooling.
□
If the circuit has an optional hot gas bypass valve, disable it
before measuring superheat and subcooling. To disable, remove
cap and backoff spring tension. Be sure to reset after checking (See
Paragraphs 8.3.3 and 9.2.4).
9.2.3.1 Check SUBCOOLING
□
Measure and record temperature and pressure of the liquid line at
the condenser coil outlet.
STEP 1) Record Measurements: Temperature =
________°F (°C) and Pressure = ________ psig
STEP 2) From Temperature/Pressure Conversion Chart,
APPENDIX, page 40, convert Measured Pressure (STEP
1) to ________°F (°C)
STEP 3) Subtract Measured Temperature (STEP 1) from
Temperature from Conversion Chart (STEP 2)
________°F (°C) - ________°F (°C) = ________°F (°C)
degrees of Subcooling
Recommended subcooling with outdoor temperature range of
70-95°F (21-35°C) is 14-18°F (7.8-10°C).
Too much subcooling indicates a refrigerant overcharge. To reduce
the subcooling, remove excess refrigerant. Too little subcooling indi-
cates a refrigerant undercharge. To increase subcooling, slowly add
R-410A refrigerant.
WARNING
Do not release refrigerant to the atmosphere. When adding
or removing refrigerant, the qualified technician must
comply with all national, state/province, and local laws.
9.2.3.2 Determine SUPERHEAT
Measure and record temperature (insulate probe from surrounding air tem-
perature) and pressure in the suction line at the compressor inlet.
STEP 1) Record Measurements: Temperature =
_______°F (°C) and Pressure = _______ psig
(continued)