We have just re-plumbed (and re-surfaced) an older in-ground hot tub that was on the property when we moved in -we replaced most of the pipe and as well as the 2-speed pump. But we just cant get the new set-up working properly. We have had a variety of error codes (HH/LF) that indicate a low-flow but just cant figure out the ultimate cause. We have a brand new filter in there (and have checked it frequently), the water level is above the intake, we have bled air from the pump, and we have also replaced both M7 temperature sensors in case they were the problem. I am hoping someone has other ideas of what to check.
Here is what happens: After re-setting at the breaker, the pump appears to complete its priming cycle, we get temperature displayed, and the pump seams to be circulating water (can see/feel output at the jets). Then..after a short while the pump stops running and we hear the heater kick on.. which then leads to the HH/LF errors - presumably as there is no flow when the water is getting heated. So it seems the pump and heater are out of sync but I don't know why or how to fix.
Another mystery that may or may not be related... the faucet before the pump was to help bleed air/drain ? from the system (This was in the original set up so we simply replaced). When it is slightly cracked open the pump appears to draw more water and the jets get more vigorous (water doesn't come out the faucet). If we open it further water will then start to come out... is this some kind of pressure issue?
I have included a picture of our set-up. Thanks for any suggestions!