Hi, I have a sundance spa older model sentry 724 which while the filter was off, a piece of twine got sucked in and now FLO error, spa won't heat. How do I find this piece of twine and get it out?? don't even know where to start so all help much appreciated. thank you!

likely to have gone no further than the intake to the pump - wrapped around the vanes of the pump impeller - undo pump union on suction - you may be able to pull it out with long nose pliers, or dismantle the pump to access and remove

thank you ffor youur sugggestion. I took the motor apart and yep, there was the twine, now I have it all back together and its working!! could not have done it without your help. thank you!

maybe you can help me with one more item.... on same spa which is sundance sentry 724, the button on the topside control which turns the blower on and off quit working. anything I can do to make it work again? or do I need a new topside control? thanks again!

we have never had 724 systems in Australia so haven't seen one.
if there is normally an indicator displaying that it is on and it doesn't work, its likely your panel will need replacement.
if there is normally no indicator, or the indicator is working but no blower, then your blower or circuit or pcb relay or triac circuit is likely at fault

my personal experiance with sundance control boards is that when the triac to run the blower fries, it's usually in the shorted condition, causing the blower to operate all the time, full speed. The part itself is only 2.30 USD, but the trick is getting someone to replace it as it's soldered in. In rare instances, however, they can open causing a no run condition.

As Alacy stated, if your indicator is showing it's on when you press the button, it's the triac, if not, it's likely the topside went bad.