Optima overheating

[sonnyo]

My optima tub is overheating and it shuts off I guess some kind of protection not to harm it further. The tub is about 7 or 8 years old.
Temp went up to 104 and then OH message came on.
Please help.

[Spa_Tech]

I would inspect the filter for age and cleanliness. If the filter is particularly old, calcified or just dirty, this may set off the OH error without affecting the pressure switch. A hint may be gleaned from the OH error clearing after removing the filter/s.
Other possibles are bad sensors.

[pkillur]

My optima tub is overheating and it shuts off I guess some kind of protection not to harm it further. The tub is about 7 or 8 years old.
Temp went up to 104 and then OH message came on.
Please help.

In addition to checking the filter (which is the most obvious choice) you could have a calcified heater as well, especially if you have particularly hard water. I helped a friend in Kansas with his tub when I was out there last year (water is very hard) and his was doing almost the same thing.  Not sure if there is a product to decalcify that actually works well.  I had ordered a "magnetizer" for my spa but it seems the product is no longer made, so it seems.  This product had indicated it helped to get calcified junk off of the pipes, etc.

[SerjicalStrike]

My optima tub is overheating and it shuts off I guess some kind of protection not to harm it further. The tub is about 7 or 8 years old.
Temp went up to 104 and then OH message came on.
Please help.

The tub should not be going into OH at 104.  I would check the actual water temperature.  More than likely, the sensor is a few degrees off and the water is hotter than it actually reads. 

[Chas]

This is from the website "HotSpring.com"

"Vanishing Act™ Calcium Remover

Reduce water hardness in an entirely new way with the Vanishing Act calcium remover. Instead of adding chemicals to the water, this product removes calcium particles, leaving the water softer and silky on your skin. Softer water reduces the need for additional chemicals, helps extend the life of your spa water, and helps protect hot tub components from damage that can result from hard water."
 
Here's how it works - first, you have to deal with the fact that it's NOT cheap. Once you get past that, it really is easy to use: in our tubs you set it on the return fitting. That's it. Come back in 24 hours and test for hardness. Not soft enough? Come back in another 24. Done.

[psubill78]

We had a simliar issue... but the water temp wasn't anywhere near that.

Had to replace the temp sensor in the filter box... old style (all plastic) was junk in these models - they redesigned to have a silver bullet tip...

[clover]

OH is a measurement of the "hi-limit" sensor, indicating the water temp at the heater is higher than the temperature in the filter bay sensor.  OR, on the other hand, the temp sensor in the filter bay is "Lieing" to the the electronics indicating the temp of the water is is 10° - 12° different than the sensor temp in the heater.

Could be a bad temp sensor.  A test plug will confirm that right away.  Secondly, you could measur ohms of both sensors which should be fairly close to each other.  OH indicates they are not.  It could be a legitimate error signal, or if the water is cool, a false reding because the temp sensor is bad in the filter bay.

You say the water is at 104°, did you measure the actual temperature or just the read out on the control panel?