Pease help, I have no heat in my Spa, had a flow check problem initially but was corrected by cleaning the filter. Worked fine for a week and now theres no heat although the panel thermostat reads high 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!

I'll bet it's clogged again.

I don't know where the temp sensor is mounted on that thing but you need to feel the temp of the heater itself when it does this. If it's hot, then you've still got the flow problem.

No flow problems, its not clogged.

The temp sensor is clamped onto the heater, and the heating element is cold. As I mentioned this all happened within a week
1.FL1 error
2. Cleaned filters, pulled Flow Check.
3. No problem
4. Week later tub got hotter than my setting of 99...
5 Then a couple day's later the water was cold, although the temp reading was 103 at the panel.

Well then,

either your temp sensor is bad or you have a defective board.

Go with the temp sensor first.
Cheaper.