Reznor MAPS III, Cabinet D RECB Users Manual - Manual (Page 9)

Form O-MAPSIII Cabinet D, P/N 222918R9, Page 9
3.5 Check
Refrigerant
Pressure and
Temperatures
(subcooling and
superheat)
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 (page 10), 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
to 95°F (21 to 35°C) is 10 to 12 degrees F (5.6 to 6.7 degrees C).
Too much subcooling indicates a refrigerant overcharge. To reduce the subcooling,
remove excess refrigerant. Too little subcooling indicates 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.
Determine SUPERHEAT
Measure and record temperature (insulate probe from surrounding air temperature)
and pressure in the suction line at the compressor inlet.
STEP 1) Record Measurements: Temperature = _______°F (°C) and Pressure
= _______ psig
STEP 2) From Temperature/Pressure Conversion Chart (below), convert
Measured Pressure (STEP 1) to ________°F (°C)
STEP 3) Subtract Measured Temperature (STEP 1) from Temperature from
Conversion Table (STEP 2): _______°F (°C) - ________°F (°C) =
________°F (°C) degrees of Superheat
Recommended superheat at is 8 to 12 degrees F (4.5 to 6.7
degrees C).
Typically, too much superheat indicates that the evaporator coil is undercharged.
Too little superheat typically indicates that the evaporator coil is overcharged and
may potentially flood liquid refrigerant to the compressor. To reduce the superheat,
adjust the thermal expansion valve by turning the adjusting stem counterclockwise.
To increase the superheat, adjust the thermal expansion valve by turning the adjust-
ing stem clockwise.
DANGER
The refrigeration circuits are high pressure systems. Hazards
exist that could result in personal injury or death. Removal,
installation, and service of this scroll compressor must be
performed by a technician qualified in R-410A refrigerant.
DO NOT USE tools or service equipment designed for R22
refrigerant. See Hazard Levels, page 2.