Looking for advice!!!!!! I have a 2004 beachcomber 350. It uses the balboa #52728 heater core. I continue to get an fl message after a day or so of use.The fl never happens when the tub is on, it will occur either when its standing by, or right after the pump is on high speed. Now I have a new pump that works fine. I have tested my flow switch and it works as its supposed to . I charged it with 12v and it is proper. On low speed it closes the circuit, and on high. When the pump shuts down it open the circuit .I have even jumped the line and im still getting a fl error code. Sometimes right away , sometimes after 4 hours of use. Its definently not a flow issue. Brand new filters and pump. I can see the heater relay open when i open the flow sensor circuit. But the pump keeps going it just wont heat. Is there another pressure switch somewhere as well? I looked at the circuit board and I only see 3 sensors. One low and high temp, and the flow switch. The circuit board is a Balboa MRSPA1. One of the temp sensors is inside the heater core and the other is leading elsewhere i believe. If the flo switch is jumped, the tub works fine, heats fine. Does it need to open that circuit when the pump stops or to prevent it from confusing the board? I am completely stumped and would love to know if anyone has any insight on this issue. When the tub is running everything is very smooth. I did read online that at times the gfi breaker on my main panel can get a bit tired and cause some issues like this. Not sure if there is any truth to that. Thanks in advance and I apologize if im all over the map with me questions, just trying to offer as much info as I can.