Hi all, hoping someone can help me out.

I have a Phoenix spa Hottub powered by a waterway 56 4hp pump. The pump had a leak so I removed it and rebuilt the pump while I had it out.

Well that was about 4mths ago and I am having trouble with the install. I have everything back in place, bled the system, and the leak is fixed...however...

The jets work fine when I manually switch them to high and low....but if I have the jets off and the thermostat triggers the heater to come on, I get a flo warning with no water movement, although I can hear the pump engage.

I can then manually turn the jets to high, flo warning goes way, then turn jets to low and it will heat and circulate properly....but anytime it turns to low/heat mode on it's own, I get no water movement and the flo warning...??

I played with the pressure switch and that seems fine.

I did find a small rubber hose, maybe a quarter of an inch wide, that is laying next to the control box. The hose is clear and appears to run up to a jet(s). There is nothing on the end of the hose but a broken off o-ring clamp. If I hold my finger over the hose and cycle the jets, there is sunction created...??

I am guessing that hose is my issue, but have no idea where it connects to??

I have a pic, but don't know how to post it?

Thanks in advance.