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Reznor RECC Unit Installation Manual User Manual

Page 67

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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 qualified 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 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

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 filter 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.)