Reznor MAPS - A,B,C Users Manual - Manual (Page 9)

Form O-MAPSIII&IV Cabinets A/B/C, P/N 257004R8, Page 9
Evaporator
Coil Cleaning
Instructions:
1. Verify that the electrical power has been turned off and the disconnect switch
locked.
2. Open the access panels.
3. Use a soft brush to remove any dirt and debris from both sides of a coil.
4. Spray with cold or warm (not hot) water and a cleaning solution (non-acid based
coil cleaner is recommended). Due to possible damage to the coil, DO NOT use
high pressure spray. First spray the leaving airflow side, then the inlet airflow side.
As much as possible, spray the solution perpendicular to the face of the coil.
Follow the instructions on the cleaning solution. When cleaning process is
complete, rinse both sides with cool, clean water.
feeders, piping connections, coil headers, and return bends for signs of fatigue, rub-
bing, and physical damage.
Clean the coils annually, or more often if needed. Use the proper tools and follow the
instructions carefully to avoid damaging the coil. Use of a non-acid based coil cleaner is
recommended. Due to possible damage to the coil, DO NOT use high pressure spray.
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 refriger-
ant. Too little subcooling indicates a refrigerant undercharge. To increase subcooling, slowly add R-410A
refrigerant.
Two important requirements before checking superheat and subcooling:
1) This unit has fully intertwined refrigerant circuits and each circuit MUST be isolated before measuring its
temperature. Another active circuit will influence the reading and make it impossible to determine accurate superheat
and subcooling.
2) If the circuit is equipped with an optional hot gas bypass valve, the valve must be disabled before measuring
superheat and subcooling. Method of disabling depends on the model and date of manufacture.
All MAPS
® IV Models & any MAPS ® III Models with a shutoff valve in the line between the compressor discharge and
the hot gas bypass valve - Locate the shutoff valve. Disable the hot gas bypass valve by closing the shutoff valve.
When measurements are complete, be sure to open the valve.
MAPS
® III Models without a shutoff valve in the line between the compressor discharge and the hot gas bypass valve
- Disable the hot gas bypass valve by removing the cover and adjusting the spring 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. To check setting, refer to Paragraph 3.9.5.
DANGER
These 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 service equipment or tools designed
for R22 refrigerant. See Hazard Levels, page 3.