Solid FLO error 99 Sundance Optima

[In Hot Water]

Temp sensor shouldn't cause a flow error.

as a "Hail Marry", 

the 24 hr circ pump  runs off TB2 at the bottom right of the board.

The "Common" white line 2 can go into this terminal,but often is directly to the terminal block where service comes in.

Line one black goes into the terminal driven by a relay. The system will periodically NOT call for the 24 hour pump to run.

At that point, if the flow remains, it has to "Halt On Error". Most of the times it is everything we have been chasing so far.

However,

If the relay is pinned feeding the circ pump on line one,... And,Common is always hot,...we have a runaway circ pump.

SO!......(this where I think I'm supposed to stop) 

https://www.thesundancespastore.com/blog/id/266/title/heat-filtration-settings-for-your-sundance-spa

Put the spa in "Economy Mode", and turn the heat setting as low as it will go. It may take a while, but this should turn off the circ pump Via the computer logic on the board. 

If you come back in a while, and the circ pump is still running, it may be a pinned relay.

Being a trained professional, I cannot tell you to move black to main terminal block, and white to unused terminal on TB2.

Common and Line have their own relays. Why, I don't know.

Moving wires around on any machine is a bad Idea. Please consult a tech to troubleshoot this spa.

[MacGuyver]

Ok so after searching around I found others talking about the wire swap option you referred to which I believe bypasses the K-10 really.

I turned the hot tub power off then I moved the black wire on the TB-2 block to the empty terminal on the left of TB-2, then move the white wire with the female connector from the left side of the main terminal block to the right side where there is also a male connection. Once I did this I turned the power back on and it flashed flo for a few seconds then everything went back to normal. I’ll let it run for a day then check on it and report back. In the meantime I’ll either be looking into a replacement K-10 relay or a whole new mother board. The relay looks to be soldered in place but I’m pretty good at stuff like that. 

[In Hot Water]

If this works, I wouldn't bother replacing the board myself, Cause I am broke.

[MacGuyver]

😂 Ya the main boards are not cheap!

I’m still interested in knowing if this bypasses the K-10 relay? If it does I wonder if it eliminates a safety feature like full shut down? 

[In Hot Water]

Not to split hares, but the circ pump is running off of K9, and K10.

If I'm not mistaken, These are in tandem. K10 and common going to terminal block is the same as K9 common, and load going to line one terminal block.

We are just flip flopping which relay drives the circ pump, and the other "Pilot Duty" leg of the 220V.

Nothing is bypassed. That would only result in halt on error failures, Kinda like what we are getting now.

[MacGuyver]

Thanks, I’m learning more about this control panel every day. 

[JBTILLE]

Whets the latest on this scenario. I've changed the flow switch like others in this post and get the flow error after a period of time. What I've noticed in my situation is that when I pull the header plug off J6 during FLO error condition, I hear a click when reinstalling J6 plug and things with the hot tub appear normal; Pumps run, heater comes on, display is clear of "FLO" error...things look and act normal. Then after some time (maybe while reaching desired temperature), FLO error reappears, and red light comes back on. When this occurs, I again pull J6 plug, hear the click, reinstall J6 plug and things look/run normal. Any suggestions??

[MacGuyver]

On 9/15/2022 at 10:43 AM, MacGuyver said:

Have you tried this? I had your same issues but after performing the following my tub has been working flawless. 👇👇

I turned the hot tub power off then I moved the black wire on the TB-2 block to the empty terminal on the left of TB-2, then move the white wire with the female connector from the left side of the main terminal block to the right side where there is also a male connection. Once I did this I turned the power back on and it flashed flo for a few seconds then everything went back to normal. I’ll let it run for a day then check on it and report back. In the meantime I’ll either be looking into a replacement K-10 relay or a whole new mother board. The relay looks to be soldered in place but I’m pretty good at stuff like that.