Finding longest pipe route from the pump

Hello, I am a newbie to Dynamo and I have been exploring the MEPover package. Would anyone know how to find the longest piping route from a specific element? :slight_smile:
This is what I’ve tried so far with bounding boxes at the start point and end point of fittings and pipes. I don’t think this is the right method too…
Capturebb

Have you succeed?