Master Spa - OHH error

[joecomputr]

First time poster here and I hope I'm posting this in the correct category.
Hoping that someone here can provide some info. I have a 2004 Master Spa / Down East / Exeter SE with a 3 pump system. An error - OHH showed up on the panel. The manual states it's an overheating problem, spa has shut down, one of the sensors has detected 118F. It says that once the heater has cooled, reset by pushing any button. This didn't work. I let it sit for 24 hrs, still no go.
A few years back, I had to replace the system control pack due to a heater malfunction. The relay blew and lost the 240 volt circuit. The unit is a MS2000, manufactured by Balboa. I still had the old one and took the temp probes from it and tried them in the one on the spa, all to no avail. It was a long shot, but figured I try. I also checked for dirty clogged filter. This doesn't seem to be a problem. The spa will not power back on, so it seems it's pointing to a control pack problem. When I reset the power, it cycles through all phases, after it checks the 240v, the OHH error shows up on the topside panel and will not go any further.
I'm hoping I don't have to replace this unit again as it was very expensive - $560 the last time, probably more now. I removed the circuit board from the old system pack and from where the sensors are, it doesn't look like I could use the old for any replaceable components. The wiring diagram doesn't show (at least to me) where the temp sensors are connected to. There are at least five fuses on the board that I can see, all checked okay.
I've called the guy who services my pool. He has serviced the spa a little, but I think his first inclination is to replace the system control pack - he doesn't have to shell out the $560+. I was hoping to troubleshoot a little more before I go that route.
Any help here? Thanks in advance!

[MaryH]

If sensors do not correct this and you did have good flo then it usually will be in the circuit board which can just be replaced without the entire control system. Did the heater ever come on before it went in to OHH? Was the heater hot when this happened?

[joecomputr]

Thanks for the quick reply Mary.
I can't say for sure that flow and heater were okay just before it went out as one day it was working fine, then the next day when I removed the cover, the spa was off (still powered up) and the error was on the panel. I've been unsuccessful in getting it to power up completely since. The last time it was used, both the heater and flow seemed to be okay.
When I replaced the spa pack before (just three years ago) the price for the entire pack was $544, while the board alone was $501. The three year life seems very unreasonable since my spa is not outdoors and exposed to the elements. It is in a cabana type structure that has good ventilation and never gets real cold inside. Does this seem normal to have to replace this twice in the 7 years or so I've has the spa?
Thanks again.

[MaryH]

Well you would definately want to get a longer life out of a system but sometimes circuit boards will malfunction without any reason. If it were me I would probably try a new high limit sensor first, the correct one that goes with your current system to see if it hasn't failed.

[joecomputr]

Is the high limit sensor that you refer to the same the sensor that are referred to as sensor A and sensor B? Is your reasoning to try a brand new one since the ones I did try were out of a spa pack that went bad? This does make sense, but I was just trying not to spend more on something that would be included with a new spa pack. I'll check to see if I can get one or two and return if it doesn't fix the problem.
Thanks Mary!

[joecomputr]

If a sensor only was the problem, would the spa go through the start-up cycle, then give either a sensor error (sna or snb) rather than not even start up at all?

[MaryH]

It could, but it could also be something in the circuit board. But before replacing a board that is why I suggested the sensor. If your system has the sensor A and sensor B on the heater those two sensors are the same part. If you have good flow out of the jets from the pump then that is why I suggest one of those two sensor may be malfunctioning.

[joecomputr]

The dilemma I'm having is that the pumps have never come on since originally getting the OHH error. I thought there was good flow out of the jets before it went out. The spa was working one day, then wasn't the next day. I've never been able to clear the error or get the pumps to start.

[MaryH]

What you can try to do is switch the two sensors at the circuit board. Plug A into B and B into A and see if it goes out of the OHH and pump comes on.

[joecomputr]

I've tried switching the two and using two sensors from an l spa pack that I had to replace a few years ago. That spa pack had a bad heater relay and I'm quite sure the sensors were okay. I've tried just about every combination of switching all the sensors I have, all to no avail. Never gets to the point where the pumps come on.
Looks like it's pointing to a problem with the board?