Cruisair HI PS message and shutdown

[mcerdos]

I have an issue with a HI PS message on a Cruisair STQ8C-HV 205363350. The unit will run for 2-3 hours with no problems. It blows cold air and the heat also works well. Then, it will shut down and display HI PS on the control panel. If I immediately restart the unit, it will run fine for another couple of hours. (On past units with this issue I had to correct the water flow issue before the unit would restart)

The instructions state this message is due to a lack of water flow and Head Pressure has risen above 400-425 psi.

The water flow is excellent. I have powerful stream exiting the vessel. I have two other units running off the same cooling pump. The problematic unit is the middle unit. I have flushed the cooling system and am certain there are no air pockets.

Any thoughts?