Reznor MAPS II Unit Installation Manual - Manual (Page 55)

Form I-MAPS II, P/N 206131 (Rev 13), Page 55
tension counterclockwise until the spring tension is relieved. Count and
record the number of turns required so that you can return the bypass
valve to its original setting.
Instructions for Checking and Adjusting the Superheat of an Isolated
Circuit:
Step 1) Measure and record the temperature (insulate probe from sur-
rounding air temperature) and the pressure of the suction line at the com-
pressor.
Step 2) From the Temperature/Pressure Conversion Chart in the APPEN-
DIX on page 58, convert the pressure measured in Step 1 to temperature.
Step 3) Subtract measured temperature in Step 1 from the temperature
taken from the Conversion Chart in Step 2. The answer is the degrees of
superheat. Recommended superheat range is 8-12°F (4.5-6.7°C).
Step 4) Superheat is adjusted at the thermal expansion valve. To reduce
superheat, turn the adjusting stem counterclockwise. To increase the
superheat, turn the adjusting stem clockwise. Adjust and check until
superheat is within the recommended range.
Step 5) Repeat Steps 1-4 for each refrigeration circuit.
Instructions for Checking and Adjusting the Subcooling of an Isolated
Circuit:
Step 1) Measure and record the temperature (insulate probe from sur-
rounding air temperature) and the pressure of the liquid line at the con-
denser coil outlet.
Step 2) From the Temperature/Pressure Conversion Chart in the APPEN-
DIX on page 58, convert the pressure measured in Step 1 to temperature.
Step 3) Subtract measured temperature in Step 1 from the temperature
taken from the Conversion Chart in Step 2. The answer is the degrees of
subcooling. Recommended subcooling range is 18-22°F (10.1-12.3°C).
Step 4) Subcooling is adjusted by the amount of refrigerant charge. To
reduce subcooling, remove refrigerant. To increase subcooling, add refrig-
erant. Adjust refrigerant and check until subcooling is within the recom-
mended range.
Step 5) Repeat Steps 1-4 for each refrigeration circuit.
 Check the compressor suction and discharge pressures and compare them
to the values in FIGURE 4 or 5 graphs in the Operation/Maintenance/Ser-
vice Manual, Form O-MAPS II, found in the owner's envelope.
 RDA/RDDA/REDA 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
18° to 25°F (10.1 to 14°C). Superheat should be in the 8° to 12°F (4.5 to
6.7°C) range.
 If the system is equipped with an optional hot gas bypass, check the valve.
Follow the instructions in Paragraph 7.7, page 28.
 If the system is equipped with an optional dirty filter switch, set the switch.
Follow the instructions in Paragraph 8.2, page 31.
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. Tem-
porarily override lockouts by raising the oC1 programmable control setting to
95°F and the heating setpoint (HSP) to 95°F. When testing is complete, reset
oC1 and HSP as required by the application. (For instructions on changing