When i turn on my Pax it shows the temperature colour and doesn't heat as it would if the mouth piece was off. Could this be from rez build up?
This is something that will regularly happen with the Pax if you don't clean it. If you search the internet and/or this forum it's been extensively covered. Short answer: it's because of a resin buildup in the pathway, on the body of the Pax where the mouthpiece connects. Clean it with an interdental toothbrush and some isopropyl alcohol and you'll be good to go.
yes. you'd be best off cleaning the part around the mouthpiece, and push a pipe cleaner up and down in that outer circle you see around the hole, where the spring is. when some resin does build up, a temporary fix to just vape anyways is to hold the mouthpiece 1/2 way pushed down till you find a sweet spot that let's it heat it up. when it gets warmer the problem dissipates for the sesh.
Ploom will also send a lube for the mouthpiece, and, if you have the original design mouthpiece, a new mouthpiece for free if you contact them.