Rheem RAMP-JEZ Installation Instructions - Page 15

The installers should balance the air distribution system to ensure proper quiet airlow to all rooms in the home. This ensures a comfortable living space. These simple mathematical formulas can be used to determine the CFM in a residential or light commercial system. Electric resistance heaters can use volts x amps x 3.414 CFM = 1.08 x temp rise Gas furnaces can use BTUH CFM = ∆T x 1.08 An air velocity meter or airflow hood can give a more accurate reading of the system CFM's. CHECKING REFRIGERANT CHARGE Charge for all systems should be checked against the Charging Chart inside the access panel cover. Before using the chart, the indoor conditions must be within 2°F of desired comfort conditions and system must be run until operating conditions stabilize (15 min. to 30 min.) ! CAUTION THE TOP OF THE SCROLL COMPRESSOR SHELL IS HOT. TOUCHING THE COMPRESSOR TOP MAY RESULT IN SERIOUS PERSONAL INJURY. IMPORTANT: Do not operate the compressor without charge in system. Addition of R-410A will raise pressures (vapor, liquid and discharge) and lower vapor temperature. If adding R-410A raises both vapor pressure and temperature, the unit is overcharged. IMPORTANT: Use industry-approved charging methods to ensure proper system charge. CHARGING BY LIQUID PRESSURE Liquid pressure method is used for charging systems in the cooling mode when an expansion valve is used on the evaporator. The service port on the liquid service valve (small valve) is used for this purpose. Read and record the outdoor ambient temperature entering the condensing unit, and the liquid line pressure at the service valve (the small valve). Locate the charging chart attached to the unit. The correct liquid line pressure will by found by finding the intersection of the unit model size and the outdoor ambient temperature. Adjust the liquid line pressure but either adding refrigerant to raise pressure or removing refrigerant to lower pressure. CHARGING UNITS WITH R-410A REFRIGERANT Checking the charge, or charging units using R-410A refrigerant, differs from those with R-22. The following procedures apply to units with R-410A refrigerant. These procedures require outdoor ambient temperature, liquid line pressure and indoor wet bulb temperature be used. IMPORTANT: ONLY ADD LIQUID REFRIGERANT CHARGE INTO THE SUCTION LINE WITH R-410A UNITS. USE A COMMERCIAL METERING DEVICE TO ADD CHARGE INTO THE SUCTION LINE WITHOUT DAMAGE TO THE COMPRESSOR. 1. Read and record the outdoor ambient temperature entering the condensing unit. 2. Read and record the liquid line pressure at the small service valve. 15