Castair Cold Start Valve CSV
The Castair Cold Start Valve (part number CSV) is a specialty valve component for air compressor systems that need startup load relief, particularly in cold-weather conditions. Listed by Castair alongside their in-tank check valve line, it's a replacement or configuration component for specific Castair compressor builds. At $5.39, if your Castair-equipped system requires this valve and it's failed or missing, this is the factory-correct part.
What a Cold Start Valve Does
- Purpose: Allows the compressor motor to start without fighting against residual head pressure. By temporarily relieving head pressure at startup, the motor can accelerate to operating speed before the compressor loads up — reducing mechanical stress and inrush current on single-phase motors
- When it matters: Cold weather thickens compressor oil and increases internal resistance. Combined with the high locked-rotor current of single-phase motors, starting under pressure can cause tripped breakers, failed capacitors, or burned windings over time
- Used with: Specific Castair compressor configurations. Castair also offers a 90-degree check valve with bleeder port (#2414025, 1/2" Flare inlet x 1/2" MNPT outlet) for DD, PK, and PP unit designations, with a repair kit available (#2414025K)
Related Castair Check Valve and Startup Components
- CSV — Cold start valve, $5.39 (this listing)
- #2414025 — 90-degree check with bleeder port for DD/PK/PP units, 1/2" Flare inlet x 1/2" MNPT outlet
- #2414025K — Repair kit for #2414025
Who Needs the Castair CSV
- Shops in cold climates where compressors start cold after sitting overnight
- Technicians replacing a failed cold start valve on an existing Castair-built system
- Anyone servicing a Castair compressor where the motor struggles to start under residual head pressure
- Installers configuring a Castair build that specifies this valve
When You Don't Need This
Most commercial reciprocating compressors use a standard unloader valve integrated with the pressure switch for load-relief at startup — that's a different component. The CSV is a Castair-specific part. If you're not sure whether your system requires it, call us with your compressor model number and we can confirm.
Technical Specifications
- Part Number: CSV
- Manufacturer: Castair (Spicer, Minnesota)
- Type: Cold Start Valve
- Category: Major Components / Check Valve family
- Price: $5.39
- Application: Castair air compressor systems requiring cold-start load relief
Detailed dimensional and thread specifications are not published online. Contact us for fitment confirmation if needed.
Why Buy From Air Compressor Factory Direct?
We stock Castair replacement components including specialty valves and check valve family parts. If you need to confirm this is the right part for your configuration, call us before you order.
- Free shipping on qualifying orders to the lower 48
- Free tech support — fitment confirmation by phone
- Full manufacturer warranty on all Castair products
Call 866-217-0063 for quick answers and help!
