A filter drier is a small, inexpensive component that does a vital job: keeping the refrigerant circuit clean and dry. Neglecting it can lead to expensive compressor failures.
What it does
- Removes moisture — the desiccant inside absorbs any water that gets into the system, preventing acid formation and ice blockages
- Traps debris — filters out particles, swarf and oxide scale that could block the expansion device
- Adsorbs acids — some driers help clean up after a compressor burnout
When to change it
Fit a new filter drier whenever you open the system for a major repair, change the oil, replace the compressor, or retrofit a different refrigerant. A blocked drier shows up as a temperature drop across it (it may feel cool or even frost up).
Choosing the right one
Match the drier to the refrigerant, system capacity and connection type, and fit it in the correct orientation (note the flow-direction arrow). Always follow proper evacuation after fitting.
FAQ
What happens if a filter drier blocks? It restricts refrigerant flow, causing poor performance, a temperature/pressure drop across the drier, and potential icing — it needs replacing.
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