Keeping the system clean and free of foreign contaminants that can restrict the operation of valves, block capillary tubes or damage compressors is the best way to assure trouble-free operation.  These contaminants can be solids, such as metal filings, flux, dust and dirt.  Other equally menacing contaminants are solubles, such as acid, water, resins and wax.

No matter how many precautions are taken during assembly and installation or servicing of a system, contaminants can find a way into the system.  Filter-driers are designed to protect a system during operation.  It is the function of this all-important unit to remove those residual elements that can attack and eventually destroy the system components.