Timed
Timed Solenoid Drains
Open at preset intervals whether or not condensate is present. Simple, but incorrect settings can waste air or leave water behind.
Compressed Air Condensate Management
How Automatic Drains Work
Automatic drains remove liquid condensate from compressed air equipment before it accumulates, carries downstream or causes corrosion. Different drain designs balance reliability, air loss and maintenance.
Quick Answer
Automatic drains open or discharge when condensate collects in a receiver, filter, separator or dryer. Timed drains open on a schedule, float drains respond to liquid level, and zero-loss drains discharge condensate without intentionally venting compressed air.
How It Works
Level-Sensing
Float or Level Drains
Open when condensate reaches a set level, reducing unnecessary discharge.
Zero-Loss
Electronic Zero-Loss Drains
Use level sensing and controlled discharge to remove liquid without intentional compressed-air loss.
Selection and Troubleshooting Guide
Practical Compressed Air Guide
| Condition | Recommended Starting Point | Why | What to Verify |
|---|---|---|---|
| Receiver tank | Reliable automatic drain sized for debris and condensate load | Prevents standing water and corrosion | Verify pressure rating and service access. |
| Water separator | Drain compatible with separator flow | Removes captured bulk liquid | A blocked drain can send water downstream. |
| Coalescing filter | Low-loss drain with good sealing | Protects filter performance and reduces air waste | Check for oil, dirt and emulsion. |
| Refrigerated dryer | Manufacturer-approved drain | Removes dryer condensate continuously | Drain failure is a common cause of water downstream. |
Interactive Tool
Preliminary Recommendation
Primary recommendation—
Supporting action—
Next step—
Maintenance and Verification
Inspect
Check operation, alarms, drains, differential pressure and visible contamination.
Document
Record service dates, measurements, element changes and unusual conditions.
Verify
Confirm that the component still meets the process requirement under peak operating conditions.
Shop Relevant Equipment
Bulk Water
Water Separators
Remove entrained liquid before it reaches dryers and fine filters.
Condensate Treatment
Oil-Water Separators
Treat oily condensate collected from drains in oil-lubricated systems.
Complete Treatment
Dryers & Filters
Browse the complete air-treatment category.
Need Help Confirming the Correct System?
Provide the equipment model, airflow, pressure, temperatures, application and current symptoms.
Related Air Treatment Resources
How Automatic Drains Work FAQs
What does an automatic drain do?
It removes condensate from compressed air equipment without requiring an operator to open a manual valve.
What is a zero-loss drain?
It is a level-sensing drain designed to discharge condensate without intentionally venting compressed air.
Why is my drain constantly leaking air?
Possible causes include debris on the valve seat, a failed seal, incorrect timer settings or a damaged valve.
Why is water still in the receiver?
The drain may be clogged, undersized, unpowered, isolated or incorrectly programmed.
Where are automatic drains installed?
Common locations include receiver tanks, aftercoolers, separators, filters and refrigerated dryers.
Do drain outlets need condensate treatment?
Oil-lubricated systems may produce oily condensate that requires treatment before discharge.