Is it necessary to install a strainer in front of a pressure reducing valve?
All TLV pilot-type reducing valves have an integral screen in the pilot section. In the COS series (with built-in separator and trap), there is an integral main valve screen. The COS-R series, however, does not have an integral main valve screen, so installation of a strainer with a minimum of a 60 mesh is recommended. In addition, in the COS series, if there is noticeable clogging of the integral screen due to dirt or scale, use the COS in conjunction with a strainer.