Castair CA6 — Genie Unloader Compression Fitting (3/8" x 1/4")
The Castair CA6 is a compression fitting in Castair's Genie unloader-type check valve series — specifically a 3/8-inch inlet by 1/4-inch outlet compression fitting. It mounts directly to 3/8-inch copper discharge tubing via a compression fitting inlet, with a 1/4-inch outlet that connects to the pressure switch unloader port or related plumbing. This smaller fitting is used on lighter-duty Castair compressors where the discharge tube is 3/8-inch diameter.
From Castair's published check valve data: The CA6 is listed under "Genie Unloader Type" with Comp. fitting inlet, 3/8" x 1/4" inlet-outlet sizing.
Genie Unloader Fitting Function
The unloader fitting performs two jobs simultaneously in the air compressor discharge circuit:
- Check valve: Prevents backflow from the pressurized tank back into the pump head when the motor is off
- Unloader: When the pressure switch opens and the motor stops, pressure trapped in the pump discharge side is released — the motor's next start is unloaded, preventing startup against full pressure
Signs that the CA6 needs replacement: motor struggles to start (tripping overload protector), persistent hissing from the pressure switch area after shutdown, or failure to maintain tank pressure between cycles.
Castair Genie Unloader Fitting Selection
| Part # | Inlet Type | Inlet x Outlet | Used For |
|---|---|---|---|
| CA6 | Comp. fitting | 3/8" x 1/4" | Smaller compressors, 3/8" discharge tube |
| CA12 | Comp. fitting | 1/2" x 3/8" | Larger compressors, 1/2" discharge tube |
| PA6 | NPT female | 1/4" x 1/4" | NPT-threaded inlet version |
| PA12 | NPT female | 3/8" x 3/8" | NPT-threaded inlet, larger size |
When to Replace This Fitting
- Motor hums and trips the overload at startup — unloading has failed, motor is starting against pressure
- Continuous hissing from pressure switch area after compressor shuts off — unloader stuck open
- Tank won't hold pressure between motor cycles — check valve portion has failed
- Visible corrosion, deformation, or leakage at the fitting body
- Scheduled maintenance — unloader fittings are wear items in high-cycle commercial compressors
Installation Notes
- Match to your discharge tube OD — the CA6 requires a 3/8-inch tube
- The 1/4-inch outlet connects to the pressure switch unloader port — confirm thread type (usually 1/4" NPT female on the switch)
- Compression fittings require clean, square-cut tube ends — deburr before installing
- Inspect the copper discharge tube end for corrosion or deformation before reusing the fitting seat
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