Went out last week and my circuit board was fried where it goes out to my heater. The pumps would work but no heat and a flashing FL1 on the display. Installed my new board #6600-288 (was a #6600-278) and i still have the FL1, So I put in a new filter, replaced the flow switch, purged all the air out of the lines, looked for stuff in the pumps that may be restricting flow and all clean. I turned off the breaker for 2 hrs and clicked it back on and the display reads FL1 before the pumps kick on. When the pumps kick on, the heater will turn on an heat but the pump stays on for only 20 min and doesn't keep going to the temp I want it at.
When the circ pump starts the FL1 goes away it is only when they are off it goes back to FL1.
What do you guys think. I am at a total loss and out of ideas.
Mike