DAB Pumps - Check Valve and Self Priming Valve for your ESYBOX and ESYBOX Mini3 

Showing how to perform the check on the valves would be useful. Discussing the symptoms as to why you would check these would make sense also. The video assumes the person understands such things, a common mistake if you are very familiar with something. Also I assume you need to turn the water/power off before removing things like this?