The Castair PC14 is a 1/4" petcock drain valve for Cast Air air compressors, used across all horsepower classes in the Cast Air lineup. At $5.08, this is a wear item — petcock drain valves corrode, clog with compressor oil and condensate, and seize closed over time, at which point the tank cannot be properly drained and moisture builds up. The PC14 is the correct OEM replacement to restore proper tank drainage and extend compressor service life.
Note: Cast Air did not provide a dedicated manufacturer product page for this valve. Specifications are drawn from the product listing. The "All HP" designation in the product name indicates this valve is used across the full Cast Air horsepower range. Contact us to confirm compatibility with your specific compressor model before ordering.
Why Tank Drainage Matters
Every piston air compressor generates condensate — water vapor from the intake air condenses inside the tank as the air cools after compression. In a humid environment, a compressor running regular shop cycles can accumulate several ounces to a pint of water per day in the tank. That condensate is corrosive. It mixes with compressor oil blow-by, forming a sludge that accelerates rust from the inside of the tank. The result is premature tank failure — rust pinholes that cause the tank to fail pressure test or, in severe cases, fail catastrophically.
The fix is simple: drain the tank regularly. A working petcock valve makes this fast and easy. A seized or clogged petcock makes it impossible. The PC14 is the part that keeps the drain functional.
Valve Specification Details
- Part Number: PC14
- Thread Size: 1/4" NPT (standard petcock drain valve thread for Cast Air compressors)
- Type: Petcock (manual quarter-turn or screw-type drain valve)
- Application: Tank drain on Cast Air air compressors — all HP classes
- Compatibility: Cast Air compressors with 1/4" NPT tank drain port
- Price: $5.08
How to Know When the Petcock Needs Replacing
- Valve is seized — will not open or requires excessive force to turn
- Valve is stuck open — leaks continuously even when turned to closed position
- Valve body is corroded or cracked — visible rust, pitting, or physical damage
- Condensate is not draining when the valve is open — internal clogging with rust or sludge
- Thread is damaged or leaking air around the valve body even with sealant
Installation Notes
- Depressurize the tank completely before removing the old petcock valve — never remove a drain valve under pressure
- Use PTFE tape or pipe thread compound on the NPT threads before installing the new valve
- Hand-tighten plus 1-2 turns with a wrench — do not overtighten, which can crack the brass fitting or damage the tank thread
- After installation, pressurize to working pressure and check for leaks at the valve body and threads with soapy water or leak detector solution
- Drain interval: after each use in high-humidity environments; weekly minimum in climate-controlled shops
When Does a Shop Need the PC14?
- Petcock is seized, leaking, or no longer functional — most common failure mode
- Compressor service/rebuild — replacing all wear items including the drain valve
- Tank was not drained regularly and condensate sludge has clogged the original petcock
- Replacement as part of preventive maintenance to avoid future seized valve during a critical job
Technical Specifications
- Part Number: PC14
- Manufacturer: Cast Air (Castair)
- Thread Size: 1/4" NPT
- Type: Petcock drain valve
- Application: Tank drain port — all Cast Air HP classes
- Price: $5.08
- Manufacturer Data: Product page not available — specifications from product listing data
What Is Included
- 1x Castair PC14 petcock drain valve
PTFE tape or pipe thread compound is not included but required for installation on NPT threads.
Why Buy From Air Compressor Factory Direct?
A $5 OEM drain valve is one of the most cost-effective maintenance parts you can stock for a Cast Air compressor. We keep these in stock and ship free on all orders. Since 2016, we have been the specialist supplier for Cast Air compressor parts — from drain valves to complete pump assemblies. If you are building a maintenance kit for a Cast Air unit, call us and we can walk you through the common wear items to include.
- Cast Air specialist since 2016
- Free shipping on all orders
- Free tech support — maintenance kit guidance available
- Full manufacturer warranty
- OEM parts — correct thread class and material for compressor tank service
Call 866-217-0063 for quick answers and help!
