1. Turn off the system and listen where the capillary tube connects to the evaporator. If you don’t hear a hissing sound, there may be a restriction at that point.
2. Apply a warm, wet rag to the side of the capillary tube that runs into the evaporator. If the restriction is due to an ice formation, a hissing sound will be heard as the ice melts and the pressures in the system begin to equalize. A restricted drier feels cooler to the touch than normal. (The obstruction within the drier prevents the free flow of refrigerant causing evaporation.)
