flo warning

I have a 2001 Sundance Altimar spa and getting Flo error. Installed a new circulation pump and new flow sensor and still getting error. If it calls for heat error goes away. Turn on pump 1 before getting error and error stays off until pump stops. If I put my finger over discharge hole and...

Filled and started the hot tub last week. Had a blinking FLO on the panel. I'm an engineer, so I investigated. The circulation pump was not working. So, today I replaced the circulation pump. Water flowing. Now I have a continuous solid FLO on the panel. Local Sundance dealer said the...