We have a Laars Lite gas pool heater with electronic ignition. Currently the unit will start up and will run fine for 5-10 mins, and then it will shut off. It clicks on start up, but there is no additional clicking after it gets going. Once it shuts down, if I turn it off and then back on, it fires up and then shuts down immediately. Any ideas on what could be causing it to shut down? The unit has a brand new control board, and there is no glow after it lights, so I am assuming the flame sensor is fine. Thanks in advance for any suggestions.