Rheem RARL-JEC Installation Instructions - Page 34

13.0 START-UP AND PERFORMANCE Even though the unit is factory charged with Refrigerant-410A, the charge must be checked to the charge table attached to the service panel and adjusted, if required. Allow a minimum of 5 minutes of run time before analyzing charge. At initial start-up or after extended shutdown periods, make sure the heater is energized for at least 12 hours before the compressor is started. (Disconnect switch on and wall thermostat off.) Connect the communicating system per Figure 5. Once all devices are connected, power up the line and low voltage to the system. When all devices are powered, the thermostat should detect the indoor and outdoor units within 45 seconds. 14.0 CHECKING AIRFLOW The air distribution system has the greatest effect on airflow. The duct system is totally controlled by the contractor. For this reason, the contractor should use only industry-recognized procedures. The correct air quantity is critical to air conditioning systems. Proper operation, efficiency, compressor life, and humidity control depend on the correct balance between indoor load and outdoor unit capacity. Excessive indoor airflow increases the possibility of high humidity problems. Low indoor airflow reduces total capacity, and causes coil icing. Serious harm can be done to the compressor by low airflow, such as that caused by refrigerant flooding. Heat pump systems require a specified airflow. Each ton of cooling requires between 340 and 450 cubic feet of air per minute (CFM). Duct design and construction should be carefully done. System performance can be lowered dramatically through bad planning or workmanship. Air supply diffusers must be selected and located carefully. They must be sized and positioned to deliver treated air along the perimeter of the space. If they are too small for their intended airflow, they become noisy. If they are not located properly, they cause drafts. Return air grilles must be properly sized to carry air back to the blower. If they are too small, they also cause noise. The installers should balance the air distribution system to ensure proper quiet airflow 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. 15.0 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: Use industry-approved charging methods to ensure proper system charge. 34