The APR control modulates the output of direct-expansion air conditioning systems, allowing less than full capacity operation for dehumidification without overcooling, the company states. Easily installed as a retrofit or in new systems, it prevents excessive compressor cycling, coil icing, and liquid slugging, says the manufacturer. The device's desuperheating chamber modulates the air conditioning system's capacity by varying refrigerant flow according to suction pressure, which changes with the temperature of air crossing the evaporator coil. According to the manufacturer, the APR control is ideal for variable air volume systems where fluctuating or reduced airflow across the evaporator can cause coil icing. Also, it is ideal for high-percentage makeup air systems where significant variations in the heat content of the outside air can cause unusually frequent system cycling, the company says.
Rawal Devices Inc., 25 Maybrook Rd., Waterbury, CT 06708; 800-727-6447; 203-596-1313 (fax); email@example.com; www.rawal.com.