Excessive Condensate and Condensation Complaints
On a recent project, a severe condensation issue was reported on several new air handling units. One report was concerning possible carryover of condensate coming off the bottom of the chilled water coil‘s. The other issue was excessive condensation on all surfaces. Walls, floors, ceiling and entering the inlet of the air handling unit backward incline fan and water all over the motor.
Hearing that there was possible condensate carryover we thought velocity was above 600 ft./m in the units. Looking through the air handler window and carefully watching what was happening there were several issues at play. What was thought to be carryover was condensate being whipped up out of the condensate pan on both the upper and lower coils and no condensate off of the coil fins. The second Observation was condensate streaks along the far wall in a particular V-shaped pattern between the upper and lower coils and condensate dripping all over the fan chamber.
One or two of the large air handler’s were turned off after hours. Carefully looking through the air handling unit and chilled water coil‘s by accident came across a hidden 1/4 to 3/8 gap between the chilled water coil’s and below the lower coil that ran across the entire coil, approximately 8 foot long. This considerable gap was allowing higher velocity air to whip up condensate and blow it out of the collection pan that looked like carryover.
The high temp high humidity air was bypassing the coils to create considerable condensation in the fan section. Strangely enough, this cooling coil bypass was not affecting the discharge air temperature which is why it went unnoticed for some time until someone looked through the window of the air handling units.
With the problem now clearly identified MSC came in during off hours when the units had time to dry. MSC techs were able to clean and adequately caulk and seal any coil bypass. After the caulk was cured, the units were reactivated for space cooling. Problem solved.