Castair SDV03M — Electronic Auto Drain (Mounted)
The Castair SDV03M is an electronic automatic tank drain — the factory-mounted version designed for direct installation as a compressor option or upgrade. Every reciprocating compressor tank accumulates water. Air drawn into the compressor carries moisture, and when that moisture is compressed and then cools in the tank, it condenses and collects at the tank bottom. Left unmanaged, this water causes internal rust that shortens tank life, contaminates downstream air lines, saturates filters, and accelerates tool wear.
Manual draining works — when it gets done. In practice, manual tank drains get forgotten, especially in multi-shift operations, end-of-day rushes, or when the compressor is in an inconvenient location. The SDV03M automates the drain cycle on a timer, opening the solenoid valve at set intervals to purge accumulated condensate without any operator action. Set it up once; it handles the rest.
How the Electronic Auto Drain Works
The SDV03M is a solenoid-operated drain valve connected to an electronic timer module. The timer opens the valve on a programmable interval — typically every 30 minutes to several hours depending on ambient humidity and compressor duty cycle — for a short programmed duration (a few seconds to a minute) to expel accumulated water. The valve then closes and the timer resets for the next cycle. The result is a tank that stays dry automatically.
Key Features
- Electronic Timer Control: Programmable interval and open duration — set the drain cycle frequency and duration to match your specific ambient conditions and compressor duty cycle
- Mounted Configuration: Factory-mounted version — designed for installation directly on the compressor as an option or upgrade accessory
- All Horsepower Compatible: Works with any Cast Air compressor HP rating — from small single-phase shop units to large industrial compressors
- Replaces Manual Draining: Eliminates the daily maintenance task and the risk of forgetting it entirely
- Solenoid Valve Design: Electrically actuated — opens when triggered by the timer, closes when the drain cycle ends, no manual intervention required
- Tank Port Installation: Installs at the existing drain port on the bottom of the tank — replaces the manual petcock
Technical Specifications
- Part Number: SDV03M
- Type: Electronic automatic tank drain valve, mounted
- Control: Electronic timer (interval and duration adjustable)
- HP Compatibility: All HP ratings
- Installation Point: Tank drain port
- Configuration: Mounted (factory installation accessory)
- Manufacturer: Cast Air (Castair)
- Price: $175.00
SDV03M vs. SDV03S — Which Version Do You Need
- SDV03M (this product) — Mounted version for direct compressor installation as a factory option or field upgrade ($175.00)
- SDV03S — Standard 115-volt standalone version, installs at the tank drain port with its own electrical connection ($119.43)
If you are adding an auto drain to an existing compressor in the field, the SDV03S is typically the simpler installation. The SDV03M is the configured version for compressor-level integration.
Typical Applications
- Any shop compressor where manual draining is inconsistent — the solenoid handles it on a schedule
- Industrial compressors in high-humidity environments where condensate accumulates rapidly during summer months
- Multi-shift operations where end-of-shift drain tasks get skipped
- Remote or unattended compressor installations where manual maintenance is infrequent
- Extending tank life on compressors that already show rust at the drain — automated draining stops the progression
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 you confirm whether the SDV03M or SDV03S is the correct version for your installation
- Full manufacturer warranty
Call 866-217-0063 for quick answers and help!
