Hello guys! I so appreciate your taking time to give advice. My son has a b-day party tommorrow night and is hoping I can get the hottub working by then. I don't know... here's the problem.

The last few weeks, the temperature of the spa seemed erratic, always to the low side. Now it won't heat at all.

Here is what I know about the tub:
* CalSpa, circa 1998 (was given to me, so I don't know more details)
* Balboa "Fiesta System" controls
* Circuit board model #51870
* 240v hardwired with 50A GFCI breaker
* 2 pumps, stainless tube style. 1 single speed, 1 two speed
* Ozone generator failed last year, not in use.

What I have done to troubleshoot:
I only have 120v to ground on either side of the heater terminals. The heater relay on the circuit board is not closing, nor is it powered. If I manually close the relay, the heater comes on.
I checked the thermocouples. Both the temperature and the limit thermocouples read about 35k ohms. Don't know if this is right, but the fact that they are both about the same indicates that they are accurate.

There are no error codes (that I've been able to determine) on the display. The entire display consists of 2 led's. One is "Heat On" the other flashes to indicate the set temperature. The "Heat On" is off, the temperature flashing indicates 100F. The actual temperature is about 65-70F (I didn't measure it, that's just my guess). All the connections seem to be tight. Plug-in connectors seem to be clean. All the fuses seem to be good. The power supply seems to be good.

My gut is telling me the controller is bad, but I'm hoping I'm wrong . Any ideas where to look next? Or, if my gut is right, what is the best (value wise) controller to get to replace this, and where would you recommend I look to buy it?

I have tried unsuccessfully to attach a picture of the controler, PCB box, and wiring diagram. If that will help, you can e-mail me at gyjunk(at)cableone.net and I will send it to you. Or give me advise on how to get a photo posted on the forum and I will edit my post to add it .

Thanks again for your advise!

1st place i'd look is the flow/pressure switch function - low flow will prevent heating - usually due to dirty/blocked filters - remove them and run spa without them to rule this out. Other than that, the pump may have a blockage, a valve mave be partially closed, an airlock after refilling, air into the suction side of the pump, or a faulty flow/pressure switch or damaged cable to the pressure switch
beyond that, you've tested sensors which sound good, so if there's no voltage to relay coils its back to a bad board or flow problem as above

Thanks for the advice! I did notice that my kids have gotten a lot of grass clippings in the tub lately (much more than usual). I'll go clear that out. The water also got too low and probably sucked air into the filter housing, so I guess that could be part of the problem as well. I'll have to play with all that tomorrow. In the meantime, here is the graphic I tried to post earlier. Mainly I'm interested in the wiring diagram. Is the pressure switch the flow switch you talked about? If so, is it a simple on/off switch? I'm very hopeful that you've steered me in the right direction!

Ok, so I looked at the pressure switch. No joy. Opens with pumps off, closes immediately when the circulation pump comes on. I also talked with a spa tech today who says that if it were the flow switch problem there would be an error code flashing on the "heat on" light. Is this so? Because there is nothing at all going on with the "heat on" light.

So, thanks again for the advice. Am I back to questioning the PCB?
- Gary

Haven't heard from anybody on this for a while. Do you agree that it is a circuit board problem? Any advice on where to look on the circuit board? I could do some simple component repairs if given advice on where to look.