My Jacuzzi hot tub keeps overheating flashing "OH". I will shut down the hot tub using the circut breaker and restart it will run fine for a few hours but than "OH" will start flashing again.

Is this an outdoor hot tub?

If it is an outdoor hot tub...is it heating up or just running all the time?

Sounds like the heating element has gone out again. Once you reset the circuit breaker and the tub turns on it will start to circulate the water. This usually runs like this for about 2 mins and then the tub will recognize it is cold and send power to the heater. If the element is back at that point it will blow the circuit breaker.
If this circuit breaker pops as soon as you turn it on then you most likely have a bad circuit board.

Rod
www.uspartscenter.com

#1. DO NOT GET INTO TUB FULL OF WATER WITH A GROUND FAULT.
2. There is a short. You need to get multimeter and start checking each part for current running to ground wire.
3) Power is ON. Connect power without GFCI.
4) Tape tester leads to wood sticks to keep hands away from power.
5) Do not touch anything directly or you will become the ground rod.
6) Ground wire must be present, and bonded back to main panel box.
7) Do not sit or touch directly on cement or bare ground. Do not touch or lean into anything made of metal.
8) Body and parts must be on sheet of plywood, or similar non-conductive dry surface.
9) Test each part with spa, but also test electric line coming from main box.
10) GFCI will also trip with any fault detected on line. So the wire coming to spa may have the fault.
11) Add a new dedicated line from main box to spa.

http://waterheatertimer.org/How-to-wire-GFCI.html
http://waterheatertimer.org/See-inside-main-breaker-box.html

If you need further help, I’m available over the phone at https://www.6ya.com/expert/gene_9f0ef4df2f9897e7

I don't ever use any cleaner other than vinegar and warm water in the jacuzzi tub due to certain chemicals which could cause problems with the breaking down of pipe glue and other o-rings and the pump sealed bearings itself...............I would run it with vinegar again for 15min which is safe to you and your family but it may be breaking down and wearing out depending on the age............Hope this helps.

Do you have a model and serial number so i can spec components and a diagram?
The reset is a GFCI electrical or a high limit temperature switch?
If its a GFCI you have a leak or a short or the pump is drawing to many amps likely due to something in the impeller or plumbing restricting flow. Potentially its a shaft seal issue.
How hot is the tub when it trips? Try running it cold and see if it trips. If it doesnt and its still cold its the pump. If its hot and you set it to cold its a stuck relay or contactor or triac and therefore tripping a high limit switch.
If this is a hot tub/spa the pressure switch may be an issue. It shuts down the heat typically and keeps the pumps running.
If a reset switch of any type is tripped to many times it will continue to trip at a lower and lower value.
Just some tips, hope they help. Get back to me with some info.

I think you had better call a repair service on this one, testing needs to be done.

Either the breaker is bad or you have an electrical problem. Unless you know how to work with electrical problems call for service. If you unplug the hot tub and plug a lamp or hair dryer into the outlet does the breaker trip? If yes, call an electrician. If the outlet is fine call for service on the hot tub.

It sounds like the bearings have gone bad in the jet pump. A shaft seal leak will sometimes let water get into the bearings and the motor will get louder and louder. Running it on high can intensify the noise and heat created by bad bearings. Eventually, the bearings will seize and the motor will try to turn and since it can't, it will get really hot. The motor has built in high limits to keep from burning up completely but it will smell like it's burning. I would replace the pump motor and seal, should take care of the problem. The OH may have been caused by the pump not moving enough water to run the heater and tripped the heaters high temp sensor. I hope this helps.

OH MEANS OVER HEAT AND THE 5N WHICH IS ACTUALLY SN IS YOUR SENSOR SO IT WOULD NEED TO BE REPLACED SO YOULL NEED TO CALL A POOL AND SPA COMPANY FOR EXAMPLE..... HOTSTUFF SPAS&POOLS SALEM,OR