I have a problem with hooking up the LP on my food truck. This part of the build has been a complete disaster so far. I’m on my fourth gas guy(first to show and do work the rest never showed/called) and when he went to hook up today nothing happened and I just got a blank stare and a $225 bill. I have hard pipe 90 out of back of my stove the the regulator then I have a T for it to split. One way for oven one way for water heater. The guy thinks its the part you screw on the tank?? He hooks tester to part on stove. When he opens the tank he gets a reading in the 10wc range but when he opens the stove knob it drops to like .6 and doesn’t come back up? Can anyone help??