A commonly observed sign that the filter drier is blocked is

A commonly observed sign that the filter drier is blocked is

• A. A pressure drop across the filter exceeding 2 psi
• B. A rise in refrigerant color
• C. A loud mechanical noise
• D. A smell of burnt oil

Answer: (A)

Blockage in the filter drier creates a flow restriction in the liquid line. The drier’s job is to remove moisture and contaminants, and when it becomes clogged, liquid flow is hindered. This restriction causes a larger pressure difference from the inlet to the outlet of the drier—the pressure before the drier stays higher while the pressure after it drops. A practical sign of this blockage is a noticeable pressure drop across the drier, commonly observed when the differential exceeds about 2 psi. If you see that, it’s a strong indication the drier is clogged and should be replaced, with the system checked for moisture or debris and properly evacuated and recharged afterward. Other signs like a change in refrigerant color, loud mechanical noise, or a burnt oil smell are not typical indicators of a blocked filter drier.

Blockage in the filter drier creates a flow restriction in the liquid line. The drier’s job is to remove moisture and contaminants, and when it becomes clogged, liquid flow is hindered. This restriction causes a larger pressure difference from the inlet to the outlet of the drier—the pressure before the drier stays higher while the pressure after it drops. A practical sign of this blockage is a noticeable pressure drop across the drier, commonly observed when the differential exceeds about 2 psi. If you see that, it’s a strong indication the drier is clogged and should be replaced, with the system checked for moisture or debris and properly evacuated and recharged afterward. Other signs like a change in refrigerant color, loud mechanical noise, or a burnt oil smell are not typical indicators of a blocked filter drier.