1.I had an FL1 error code and cleaned the filters and removed the downstream lime just before the circulating pump to make sure the flow was good.

2. I also removed th flow check valve a Harwil that the owners manuel said to check.

3.After installing the filter and the check valve everything worked great. Two days later I had an FL2 error and found that I hadn't turned the Flow Check all the way towards the direction of the flow arrow. Corrected this and everything was normal to error codes.

4. a few days later theres no heat although the panel thermostat reads 103 and the water is cold. It has a circulation pump an electric stainless heater approx. 2' long and a Harwil Flow control.

What are the diagnostics checks can I do and the specifications. I checked the Flow control with an OHM meter and found 8 ohms resistance, I dont know if this is right either. Could this NO HEAT problem be a malfunctioning Thermostat. The circulation pump will go on but then aftere a minute goes off becuase the temp reads 103 degrees with the water cold. I just dont know where to start.Help thanks!

Temperature Sensor or Circuit board.

Those are the only things left that'll cause this problem.