Fantom, I may a bit out of my element as I am new to the forum myself, but I have the same FL1 error. I believe that means that the flow switch is registering no water flow through the circulation pump circuit. It could be: A) because the flow switch isn't working properly (i.e. broken or stuck) - even though there is water flow, or B) because there truly is no water flow. I think that is why you aren't getting any heating, because the controller THINKS there is no water flow and since the water is heated as it runs through the circulation pumps, if the controller thinks the water isn't flowing, then it won't turn on the heater. BTW, over time, I assume your temperature will continue to drop.
So you first need to figure out if the water is flowing or not. Since you have suction, you should have water flowing out of the "aerating" outlet. If that is true, then it is likely you have a problem with your flow switch. If you read this and reply, then we can keep going on this together...but it's been a few days since you posted this, so perhaps you've already fixed it. If so, please let me know what you did. Thanks.
