Carrier 40QA500067 Filter 323080 701 direct acting water regulating valve designed direct acting water regulating valve designed specifically for maintaining stable head pressure in water cooled condensers Contractors often specify the SET29A 629R for maintaining stable environmental conditions where standard sensors fail to meet the rugged requirements of water or glycol systems replacing this filter is a standard procedure to prevent high limit trips and ensure the Carrier air handler maintains optimal heat exchange efficiency this filter is engineered to maintain low static pressure while protecting the evaporator coil from particulate buildup