Had 'Cal-Spa' delivered and filled it up. Followed the manual instructions to START but no water flow. Got ERR msg on panel. Called the 800 Customer Service # and the tech there said to undo the union..gurgle etc Then restart. That worked. A friend bought a used 1 yr old spa (different brand) this Summer and had the same problem on startup, Same procedure worked. Some arent made with bleeders and sadly, you weren't there to give sage advice when the units were bought
R