How do I check my system or parts for leaks?

There are multiple ways to do this. The traditional method is with a 24 hour leak test, filling the system with paper towels after a last go-over of the system to ensure all the fittings are tight and all the spare ports are plugged, valves closed, etc.. Power only the pump by placing a jumper on the 24 pin connector and run the loop for a day, checking in on it periodically to inspect for leaks. If it passes, it’s generally good to go. Another method gaining popularity is air pressure testers. While not perfect, they are fairly reliable and can be used to test individual components before even assembling the system. If testing a full system with one over a longer period of time, keep in mind that ambient air temperature fluctuations can change the pressure reading. It’s also important to note both that CTR style reservoirs can’t handle a lot of pressure and that you cannot pressure test a full loop that has a fitting for relieving pressure, just the individual components.