New to me Bullfrog 451

[bullfrogjake]

Hello all,
I'm new to the forum after purchasing a used 2003 model Bullfrog 451. Wondering if anyone out there has had this issue....My Jets will run on low randomly in what is referred to as automatic spa control. Apparently this occurs on this model when a freeze condition is detected, heat is called for, or during a filter cycle. During this time, my standard control panel lets me switch between hi/low jet speed but not turn them off. The only way to stop the pump is to press the temp/light buttons to go into standby mode. The issue is all parameters are met, so I'm hoping someone has had this same issue and has found a faulty temp sensor, etc. At one point for a few hours after playing with buttons the tub functioned normally but was back to acting up again the next day. Of course I would rather not just replace the control panel (which btw already has a new one installed from past problems) or a motherboard unless I have to. Any feedback would be greatly appreciated.
Jake

[Jacuzzi Jim]

 If I read that right?    If it's calling for heat the 2 spd pump will run until the set temperature is met.  A faulty temp sensor is fooling the system to call for heat even though the set temp is where it's at or it's in a filter cycle.

  Most likely a bad sensor.    Try leaving it in std mode and drop the temp as low as it will go see if the pump shuts off.  Another would be is the water hot or cold?  Well as cold as it can get in this heat it's like a 1000 degrees across the country.   If it gets too hot the Hi-limit will trip.

[bullfrogjake]

Jim, the temp setpoint seems to be working. The tub will heat to whatever temp i set it to and then cycle off. I'm thinking that if this is working, it can't be whats keeping the pump on unless there is a secondary sensor somewhere? i have cycled the heater on/off several times to test it and it seems to be working. The last time i looked, the temp diplay showed 97 and i dropped the setpoint to about 85. The heater indicator light is off but the pump won't shut off. I'm not sure if there is another sensor triggering a freeze condition or maybe the filter cycle is hanging up??

[Sam]

If I understand what you are saying, I don't think there is anything wrong.  The low speed will also  run during the pre-programmed filter cycles.  Factory default is 2 times per day at 2 hours.  You can change that though.  I've seen people accidentally change it to a much longer time and think that their spa never shuts off.

Hope that helps

[bullfrogjake]

I got busy this week and am just now getting back to this. The filter cycle thing may be my problem! I'm trying to read up on the filter cycle durations and the manual has no detail. The dealer in my area also hasn't returned my call. I can choose filter cycles F2, F4, or F6. When the tub was constantly running i chose F6 thinking it would call for a cycle every 6 hours. Maybe it is trying to run for 6 hours twice a day. That may be some of my issue. I'm not home at any one stretch long enough to monitor it. It does however occasionally come on for just five minutes also, which confuses me. None of this is a really big deal, i'm just trying to figure out how this thing is programmed!

[Jacuzzi Jim]

 Yes I believe it is running 6 hours twice a day.  Everything runs on a  12hr cycle for the most part.  Set it to F2 and see how it does.   

[bullfrogjake]

Yup I believe I have the cycle setting figured out. It does run twice a day for two hours each when set on F2. The pump continues to cycle on for a couple of minutes intermittently however. Here's an odd finding.... I pulled sensor A then B from the board to do a continuity check on the sensors. The tub sensed they were unplugged and shut down. This is normal I assume. However when testing for resistance on both temp sensors (#30382) they both read infinity, or open circuits! Yes, I have positive contact on each lead and have my meter set to read ohms of resistance. How in the heck does the motherboard know I unplugged the sensors if they are both reading open circuits? now I'm totally at a loss Another thing that would be great to know is what each sensor is used for. One is before the heater and one is after.

[Jacuzzi Jim]

 Ones a high limit the other is a temp sensor.  There should also be a pressure switch screwed onto the SS tube?   If you un plug it from the board, the system basically says ok something is missing or wrong and shuts the heater off.