Castair SDV03S — Electronic Automatic Tank Drain, 115 Volt
The Castair SDV03S is a 115-volt electronic automatic tank drain valve designed to eliminate manual condensate draining from any reciprocating air compressor tank. It is compatible with all horsepower ratings — from small single-phase shop units to large industrial compressors — and installs at the existing tank drain port as a direct upgrade to the manual petcock.
Water in a compressor tank is one of the most common causes of accelerated tank wear and downstream air quality problems. Every reciprocating compressor pulls moisture-laden air in with every stroke. That moisture condenses in the tank and accumulates at the bottom. Without consistent draining, you get internal rust that shortens tank life, water in the air lines that saturates downstream filters and damages pneumatic tools, and eventually a compressor tank that fails before the pump does. Manual draining works when it actually gets done — the SDV03S makes sure it happens on schedule, automatically, without any operator involvement.
How It Works
The SDV03S uses a solenoid valve controlled by a programmable electronic timer. You set the interval (how often the valve opens) and the duration (how long it stays open). At each interval, the timer triggers the solenoid, the valve opens, accumulated condensate gets expelled from the tank bottom, then the valve closes and the timer resets. In high-humidity environments you might set it to drain every 30–60 minutes. In a dry climate with lighter use, a 4–6 hour interval may be sufficient. The key is that the decision is made once at installation, not every day.
Key Features
- 115 Volt AC Operation: Standard single-phase shop power — connects to the compressor's electrical panel or a standard 115V outlet
- Electronic Timer Control: Programmable interval and open duration — adjust drain frequency and duration to match your ambient conditions and compressor duty cycle
- Universal HP Compatibility: Rated for use with all compressor horsepower ratings — the same valve works on a 5 HP shop compressor or a 25 HP industrial unit
- Tank Port Installation: Threads into the tank's existing drain port — replaces the manual drain petcock
- Solenoid Valve Design: Electrically actuated — opens on timer signal, closes when cycle ends, no mechanical actuation or manual intervention required
- Eliminates Manual Draining: Set the timer once; the SDV03S handles condensate removal on every cycle without anyone having to remember to do it
Technical Specifications
- Part Number: SDV03S
- Operating Voltage: 115 Volt AC
- Control Type: Electronic timer (interval and duration programmable)
- HP Compatibility: All HP ratings
- Installation Point: Tank drain port
- Manufacturer: Cast Air (Castair)
- Price: $119.43
SDV03S vs. SDV03M — Which Version Do You Need
- SDV03S (this product) — 115V standalone field-install version. Replaces the manual petcock on an existing compressor. Connects to a 115V power source. ($119.43)
- SDV03M — Mounted version configured as a factory or upgrade option for direct compressor integration ($175.00)
For most shops adding an auto drain to an existing compressor, the SDV03S is the correct choice. The SDV03M is the factory-integrated configuration.
Typical Applications
- Any shop compressor where manual daily draining is inconsistent or frequently skipped
- Compressors in high-humidity environments — summer months in humid climates generate condensate rapidly, and a timer-based drain keeps up with it automatically
- Multi-shift shops where end-of-shift drain tasks get missed during handoff
- Compressors in back rooms or inconvenient locations where manual draining is genuinely inconvenient
- Extending tank life on any compressor — dry tanks last significantly longer than tanks with standing water
Why Buy From Air Compressor Factory Direct?
- Authorized Cast Air dealer since 2016
- Free shipping on qualifying orders
- Free technical support at 866-217-0063 — we can help confirm the SDV03S fits your tank drain port and answer questions about timer programming
- Full manufacturer warranty
Call 866-217-0063 for quick answers and help!
