A restriction is a blockage in the refrigerant path, usually at the filter-drier or capillary tube, caused by moisture, debris or oil sludge. Symptoms resemble a refrigerant leak: the unit runs but doesn't cool, and the evaporator shows little or no frost. Repair involves recovering refrigerant, replacing the filter-drier and clearing or replacing the capillary tube, then evacuating and recharging.
Restriction vs. Leak
| Indicator | Restriction | Leak |
|---|---|---|
| Cooling | Poor or none | Gradually worsening |
| Frost on the filter-drier or cap tube | Often (cold spot at the restriction) | No |
| Condenser temperature | Often cooler than normal | Cooler than normal |
| Partial restriction from moisture | Cooling cycles on and off as ice forms and melts | N/A |
Causes
- Moisture in the system from a previous repair without a proper vacuum
- Debris or scale from brazing without a nitrogen purge
- Compressor oil breakdown after a burnout
- A saturated filter-drier
Repair
- Confirm the restriction location.
- Recover refrigerant.
- Replace the filter-drier; clear or replace the capillary tube.
- Flush if contamination is present.
- Pressure test, deep vacuum and weighed charge.
Typical Cost
| Repair | Typical range |
|---|---|
| Capillary tube / filter-drier restriction repair | $1,195 – $2,250 |
Typical totals for parts and labor in the Las Vegas area. The $75 service call is credited toward your repair, and every repair is backed by a 1-year parts and 180-day labor warranty. Your exact price depends on the model, the part and access, and you approve a firm quote before any work begins. Full price list →
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