I am trying to get the pool heater to kick on. Instead of the heater igniting, I am receiving a fault code of “Open Air Pressure Switch” and the SERVICE LED is light. Is this something that I can easily reset or do I need a technician to come out?

I am not familiar with them. It sounds to me like there is a switch that stops ignition if there is a problem with combustion air supply. Check the air supply. Look for some kind of a switch. Could be as simple as a loose wire. If the switch seems to be bad, it could something you could pick up at a local electrical supply house.