View Full Version : Heat exchanger ahu pressure? Drip tray leaking?

26-08-2016, 07:53 AM
Hi guys
So yesterday i went to investigate a leak coming from the ahu, it seems the drip tray is over flowing and coming out of the side panels instead of the condensed drain.
I have a feeling that there is a build up of negative pressure or something due to blocked filters as all 5 units have same problem. How ever each unit has a j-trap as the condense pipe comes out of the unit, could this be an issue?

Has any one gt any ideas or experienced this?

Thanks guys

The Viking
26-08-2016, 11:40 AM
Blocked filters or dampers could be an explanation.
It could also be the velocity of the air sucking the water droplets from the coil and dragging them outside the tray.
Have seen this happened when the controls for the dampers in the mixing chamber failed and left both sets of dampers partially closed.

By measuring the negative pressure inside the AHU you can measure if the traps are big/tall enough. (Get the pressure in to mmAq, multiply with 1.5 and measure that the height differential of the trap, in mm, exceed the result of your calculation).