Water Contamination & Ice Blockage
Diagnosis, physical separation, molecular sieve drying, and nitrogen blanketing protection for water-free coolant systems after water ingress. 6 real cases analyzed in depth.
6 Ice Blockage Cases
4 Water Removal Methods
5 Protection Design Steps
Water Contamination & Ice Blockage
Diagnosis, physical separation, molecular sieve drying, and nitrogen blanketing protection for water-free coolant systems after water ingress. 6 real cases analyzed in depth.
Why Water-Free Coolants Fear Water
LM-11D, LM-11F, and other water-free coolants are designed specifically for ultra-low temperature applications. Their core advantage is the absence of water in the system. However, once moisture enters, it rapidly freezes at -40C to -60C low temperatures, causing pipe blockage, pump seizure, and localized heat exchanger icing - potentially leading to equipment damage.
2025 technical support data shows that LM-11D water ingress and ice blockage is the most frequent problem type, occurring 6 times in 34 typical cases, covering multiple water ingress pathways and ice blockage manifestations.
Main Water Ingress Pathways
- Residual water in pipes not drained - after system cleaning or testing
- Open tank admitting water - open tanks in contact with air, moisture condensation enters
- Water used for pressure testing - water-prohibited systems mistakenly using water for leak testing
- Air moisture condensation - moisture ingress at system openings in humid environments
Ice BlockageDiagnosis & Solutions
Pump Seizure & Pipe Blockage
Low-temperature moisture freezing causes pump seizure and pipe blockage. After temperature rises, ice melts and the pump restarts, but the problem is not resolved. Solution: Physical separation - let stand to stratify and collect upper coolant. Molecular sieve drying - treat residual moisture. Install filter before pump with regular cleaning based on operating current.
Cooling Difficulty & Moisture Detection
Moisture detected in system (e.g., 104 ppm), cannot cool below -40C. Plate heat exchanger locally iced, blocking heat transfer. Solution: Drain coolant and let stand to stratify, collecting upper portion. Thoroughly blow-dry system. Use dry nitrogen for pressure leak testing. Long-term: nitrogen blanketing and sealed tank.
Molecular Sieve Ineffective
Molecular sieve used but water removal is unsatisfactory, water content still high. Solution: Try adding alcohol to lower water freezing point (Beijing lab showed some effect). More thorough approach: physical separation followed by molecular sieve drying.
Leak Testing Water-Prohibited Systems
LM-11F and other water-prohibited systems cannot use water for pressure leak testing, as water will remain in the system. Solution: Use dry nitrogen for pressure leak testing to ensure the system has no leaks and no moisture residue.
Ice BlockageReal Cases
Anti-Ice BlockageSystem Design Essentials
Nitrogen Blanketing
Use nitrogen blanketing on the tank to isolate airborne moisture. This is the most effective measure to prevent water ingress in water-free coolant systems. Maintain nitrogen blanketing pressure at a slight positive pressure.
Sealed Tank Design
Use closed-loop tanks or sealed expansion tanks to avoid direct contact between open tanks and air. Position return lines at the bottom of the tank to reduce agitation and gas entrainment.
Dry Nitrogen Leak Testing
Water-prohibited systems must never use water for pressure leak testing. Always use dry nitrogen for pressure leak testing to ensure system tightness without introducing moisture.
Pre-Pump Filter
Install a filter before the pump to intercept precipitated crystals or ice crystals. Clean the filter regularly based on operating current changes to prevent blockage.
Water Content Monitoring
Regularly test coolant water content. LM-11D used below -40C should have water content controlled at extremely low levels (recommended below 50 ppm). Investigate water ingress sources immediately if water content increases.
Physical separation: Uses density difference; after standing, coolant and water stratify. Collect the upper coolant layer. Suitable for initial separation of large water volumes.
Molecular sieve drying: Treats trace residual moisture after physical separation. Note: effectiveness may be limited; use in combination with physical separation.
Alcohol freezing point depression: Add appropriate alcohol to lower water freezing point as a temporary emergency measure, not a long-term solution.
System blow-drying: Use dry nitrogen to purge system piping, removing residual moisture. Suitable for drying after system cleaning.
Ice BlockageFAQ
Solution: Physical separation: let stand and stratify, collect upper coolant. Molecular sieve drying: use molecular sieves for residual moisture. Recommend nitrogen blanketing for water tank. Install filter before pump, clean regularly based on operating current
Solution: Drain coolant, let stand and stratify, collect upper portion. Thoroughly blow-dry system. Use dry nitrogen for pressure leak testing. Long-term: add nitrogen blanketing, seal water tank
Solution: Use dry nitrogen for pressure leak testing to ensure no leakage points
Related Topics
Complete Coolant Selection Guide
Water-free coolant selection strategy
Cooling Performance Troubleshooting
Troubleshooting cooling difficulty caused by ice blockage
LM-11 Series Coolant
Technical details of water-free coolants
Pressure Anomalies & Safety Design
System pressure issues caused by ice blockage
Post time: Aug-27-2026