Why Water Spits Out of the Top Exhaust on CW-H Models


This article explains why water may spit or spray from the top exhaust of CW-H Climate Wizard coolers (CW-H10, CW-H15, CW-H15S, CW-H15S Plus). It covers common causes such as closed dampers, incorrect airflow balancing, excessive static pressure, misaligned cores, and unflushed heat exchangers. Includes troubleshooting steps, preventive measures, and a quick reference table for airflow and static pressure specifications. 

Attached Manual Pages: Installation & Operation Manual pages 11–13 (installation and airflow balancing), page 32 (airflow balancing details), and page 43 (troubleshooting water carryover).


Issue Summary

Water is observed spitting or spraying from the top exhaust of CW-H Climate Wizard coolers (models CW-H10, CW-H15, CW-H15S, CW-H15S Plus) during operation.

Quick Reference Table: Model Specifications

Model

Supply Airflow Rate

External Static Pressure

CW-H10

800 L/s (2880 m³/h)

200 Pa (0.80 in.w.g.)

CW-H15

1000 L/s (3600 m³/h)

175 Pa (0.70 in.w.g.)

CW-H15S

1100 L/s (3960 m³/h)

175 Pa (0.70 in.w.g.)

CW-H15S Plus

1600 L/s (5760 m³/h)

210 Pa (0.84 in.w.g.)

Possible Causes

  1. Closed or Restricted Supply Air Ducts
    • Running the cooler against closed dampers or blocked ductwork increases internal plenum pressure, forcing water out through the exhaust.
    • Manual Note: Always ensure dampers are fully open before starting the cooler.
  2. Incorrect Airflow Balancing
    • The cooler splits air into supply and exhaust streams. If the supply transition damper is not set correctly, excess air can push water from wet channels into the exhaust.
    • Refer to the table above for correct plenum pressures.
  3. Excessive External Static Pressure
    • Undersized ducts or too many bends increase resistance, causing high pressure and water carryover.
  4. Core or Spreader Misalignment
    • If heat exchanger cores or water spreaders have shifted during transport or maintenance, gaps allow water to escape into airflow.
  5. New or Unflushed Heat Exchangers
    • Newly installed cores can cause foaming or water pull-off until flushed. The manual recommends flushing cores during commissioning.

Troubleshooting Steps

  1. Check Supply Dampers
    • Confirm all supply air dampers are fully open before starting the cooler.
  2. Verify Airflow Balancing
    • Adjust the supply transition damper to maintain correct plenum pressure for the specific model.
  3. Inspect Ductwork
    • Ensure duct sizing and layout do not create excessive static pressure.
  4. Check Core and Spreader Alignment
    • Inspect internal components for proper fit and sealing.
  5. Flush Heat Exchangers
    • If recently installed, flush cores with fresh water and drain the reservoir as per commissioning instructions.

Preventive Measures

  • Always follow commissioning guidelines for airflow balancing and core flushing.
  • Regularly inspect ductwork and cooler components during maintenance.
Reference: CW-H Installation, Operation & Maintenance Manual (Seeley International).