Never connect a water cooler to the system it is going to cool directly, fill with water, and start the water circulation. You are bound to inject some dirt, rust particles etc. into the system, risking to clog the water ducts inside.
This was done with one of the Albanova closed circuit water coolers with four separate circuits driven by one pump. But it applies to any kind of water cooler to be connected to some system to be cooled.
So I first connected a water filter and a flow meter to the water cooler, filled up to 2 bars pressure, and started the pump. I let it run for about 10-20 minutes, and then connected the filter and flow meter to the next circuit. And so on for all four circuits.
When I was done I took out the filter for inspection.
The used filter is of course the one in the bucket. For comparison I placed a fresh filter and a dissasembled filter housing next to it.
In the bucket there is a lot of dirt and rust particles, and the whole filter is brownish from the dirt it has collected.
The water visible at the flow meter looked clean and clear most of the time, except at the very first seconds when the circulation was started.
A. Liljeborg, 2015-09-10