morrisey0

Just in case someone runs into this thread with a similar FLO problem, I solved my issue today so maybe it can help. Earlier this week, my local Sundance service tech came by, looked over my wiring, measured a couple of things, and agreed that the new board I got was DOA. SInce it is going to take weeks for the retailer and Sundance to test out the board to prove that it is bad and then send me a new one, I decided to experiment with the original board that was giving me the FLO and FLO2 issues. BTW, while the tech was at the house, I asked him about the circ pump running 24/7, and he confirmed exactly what I have read on the internet over and over, and that is that it does run all of the time. I told him that I believed that it used to not run all the time, and he said he had never heard of any such thing. I go back to thinking I am crazy. I pulled the relay off the old board that switches the one leg to the pump that isn't straight wired. Low and behold, the switched contacts were closed all of the time, keeping the pump running all of the time. I pulled the relay next to it (that would switch the other leg to the pump if it were wired to the board), and swapped it into the place of the bad relay. Waalaa, the tub is back to operating perfectly.............................and the circ pump will turn off after the setpoint has been met and maintained for a while. So, outside of dropping $400 on a board I didn't need, all is well. So, just for future reference, there are Sundance 850 boards out there that do not run the circulation pump 24/7, and a FLO (and FLO2) error can be caused by having water flow when the board doesn't want water flow....................ie, the pump runs all the time.

Okay, so the above is a bit long winded, and a bit more information than what is required for the current issue. Let me get to the jist of my current problem. With original circuit board installed, the display works fine and circ pump runs and everything seems okay, except I have a "FLO" problem. If I work around the "FLO" problem by letting the water temp reduce, then reset and bump up the temp setting, the tub can actually be functional. With brand new Sundance circuit board out of the heat sealed bag, and jumpers set exactly like the old board, I get a few random crystals light up on the display for about 20-30 seconds, and then they go out. No pumps come on and the tub seems dead. I have voltage across all of the fuses. The transformer should be fine since it runs the old board fine. I have swapped out the new board back and forth with the old board twice now, and get the same results. Anyone know what my problem could be, outside of a new DOA circuit board? Thanks for any help!!

I purchased this tub approximately 2.5 years ago from a local Sundance dealer. It was owned by a customer of theirs that upgraded to a newer tub, and they took in on trade. It had been serviced by the dealer it's whole life. From some of the dates that I am seeing on the components, it looks like many parts were replaced prior to me purchasing it, as if they maybe "rebuilt" it to a degree before selling it off. No problems with the unit at all until about six weeks ago. Board: Sentry 850 LCD - 850 NT 6600-092 The board case is stamped 7/03. I powered the hot tub off of an existing 30A dryer circuit (switched over to gas dryer), so I had the dealer make the changes to the settings/pins needed for the unit to run at only 30A. The jumpers are set as: JP20 - Open....JP19 - All Open.....JP9 - 5, 9, & 11 are jumped, all others open. I am not sure if J9-9 being jumped is correct since this is a single pump model. On the sensor harness, the flow switch goes to the center top and bottom, and two other cables use the far right tops and bottoms (assumed temp sensors). There is a small jumper between the upper #2 (from left) and the lower #1. My first issue was six weeks ago, but it shouldn't have anything to do with the current problems. The air blower stopped working when it had voltage. Pulled the motor and the brushes were worm to almost nubs and carbon dust was all over the place. The motor was stamped 2009 and probably had less than 20 hours on it since I bought it. Chalked it up to bad armature and haven't replaced it yet. Four weeks ago, the wife was getting out of the tub and goes to turn the jet pump off (cycle from low speed to high to off), she hears a click and the display goes blank. It tripped the panel breaker, and when I reset it, still nothing, then find the board 30A slo-blo is blown. Replace it and the circulation pump won't come on while it has voltage. Pulled the pump and find no signs of water at the ECM board, but it stinks bad and it obviously done (also stamped 2009) and I figured it blew the fuse on it's way out. Order a new one, install it, and it runs fine with more flow than previously. Then the first time my wife uses it for 30 minutes or so, everything goes fine, and then when we both go to get into it a couple of hours later, the dreaded "FLO" is on the display and no controls work. The circ pump is running, and there is plenty of suction at the filter inlet and the flow switch is visibly closed. Reset it a couple times, and everything works for a few seconds, then FLO. After some experimentation I have found that it acts like many of the others that I have read about, and only does the FLO error when it has reached setpoint temperature. If the water temp is lower than setpoint and heat is on, I have all of the controls and the jet pump works along with the heater, etc. The heater turns off on high jet pump speed as it should on 30A, and the unit acts completely normal until setpoint is met, then FLO. If I leave it on until the next day, it will read FLO2 the next morning. The flow switch ohms out fine, but I order a new one anyway and install it. No change. One observation that may only exist in my mind. Can the unit be set up to not run the circ pump all the time? I do not believe that prior to this happening that the pump ran constantly but it does now. Everywhere I have read says that it does run 24/7, but I don't think it did previously (again, maybe just in my mind). Now the weird part. When it is at setpoint temp and the FLO error has come on and locked out the controls, if I block the pump inlet and the flow switch opens, FLO goes away and the panel comes back. Open the inlet back up so that the flow switch closes, and the FLO comes back. It is weird that it seems to think that it has a flow problem until I actually stop the flow, and then it seems to think all is well. I have a strange theory that has to do with it actually getting flow when it doesn't want it, but I can't find anything in my reading that comes close to supporting that, and again, everything I have read says the circ pump runs all the time. So, after all of that, I decide that I just need a new board. I figure the recirc pump damaged the board on it's way out. New board comes in today, and I swap it out with the jumpers and everything exactly how it was on the old board......................and I get nothing! Some crystals will light on the dispay for a few seconds, then the display goes blank and nothing responds. I am getting voltage on both sides of all of the fuses, but nothing is happening. I am thinking now, on top of everything else, I got a bad new board. Thanks for any suggestions that could help me out!!!!!!