To be able to disconnect the radiator from the machine chassis, tube coupling connectors are needed. While there are many connectors on the market, it was important to us to be able to open the cooling loop without any water spilling out. Below you see the QD4 series connectors, also manufactured by Koolance. Of course we tested how well the no spill feature works when the cooling loop is active. As it turned out it works really well. Only one or two drops of water were present on the connectors and the instant system shutdown worked as advertised.

Unfortunately for us the 3U server case did not offer enough room to install quick connect couplers on the CPU cold plate. Instead we took the normal connectors there which worked fine too. We cut off a few 20-25cm long pieces of the tube that were then used to install the connectors. Simply push them over the connector and gently turn until it goes no further, then carefully pull off the tube while maintaining the torque direction. The installation of the cooling loop tubes was a two person job. One to hold and turn the tube and the second person needed to pull the clamps over the tube to seal it properly. Once installed you have to be really careful to prevent torque on the tubes that could easily loosen the connectors leading to water spill. The only drawbacks we experienced with those connectors were the installation process and handling of the tubes after the installation. If you have enough room we recommend installing the no-spill quick connectors on the CPU cold plate.

When it comes to water tubes there are a lot of options you can choose from. Since we do not care if the tubes glow under UV light we went for tubes from the PrimoFlex Advanced LRT series. They work well in small spaces because of they can be bent in a tight radius without the tube collapsing. The tubes are also polished on the inside to minimize the surface area biological contaminants can stick to. Another plus point is that they are manufactured without hazardous chemicals inside. One important thing we had to do was to wash out the tubes with hot clear water before connecting them to the cooling loop. There was quite some dust inside because the ends of the tubes were not sealed wherever the supplier had stored them. When cutting the tubes make sure you have a really really sharp knife with a long blade. You want to cut the whole tube in one go. It also helps to squeeze the tube just a tiny weeny bit to even out the down pressure from the knife to make sure you get a clean cut. If done right you get a straight cut that is not curved in or slanted at the end.

Metal clamps are used to fix the tubes on metal connectors and keep the water from escaping. Those clamps are a really tight fit, but only four of them were needed. A pair of channel locks was used to loosen the clamps and pull them over the tubes. Since the space on the CPU cooler is very narrow, you have to be extra careful.