Reznor MAPS III - Page 67

Form I-MAPSIII&IV, P/N 222917R9, Page 67
STEP 2) From Temperature/Pressure Conversion Chart, APPENDIX, page
72, 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 68
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 subcool-
ing, remove excess refrigerant. Too little subcooling indicates a refrigerant under-
charge. To increase subcooling, slowly add R-410A refrigerant.
WARNING
Do not release refrigerant to the atmosphere. When adding or
removing refrigerant, the qualied technician must comply with
all national, state/province, and local laws
.
Instructions for Checking and Adjusting the Superheat of an Isolated Circuit:
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, APPENDIX, page
72, 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 range 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 ood 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
adjusting stem clockwise
RDB/RDC/RDDB/RDDC//REDB/REDC only - Check the re-heat heat pump circuit
refrigerant subcooling and superheat. (Refer to the instructions above for checking
superheat and subcooling.) Acceptable subcooling readings range from 10 to 12
degrees F (5.6 to 6.7 degrees C). Superheat should be in the 8 to 12 degrees F
(4.5 to 6.7 degrees C) range.
 If the system is equipped with an optional hot gas bypass, check the valve. Follow
the instructions in Paragraph 7.7.
 If the system is equipped with an optional dirty lter switch, set the switch. Follow
the instructions in Paragraph 8.1.2.
 If blower speed adjustment is needed to accomplish proper air balance, see
Paragraph 6.6.
10.3.2 Startup Checklist
for Systems with Gas
Heat Module
 Establish a call for heat. Observe for changeover and complete sequencing.
Sequence of Gas Heat Operation:
NOTE: Outdoor ambient lockouts will prevent mechanical gas heating. Temporarily
override lockouts by raising the cooling mode lockout setting to 95°F and the discharge
air heating setpoint to 95°F. When testing is complete, reset setpoints as required by
the application. (For instructions on changing settings on the programmable control,
refer to the instruction sheet in the Literature Bag or with the Wiring Diagram.)