how we reset tripping ?

It's hard to say without more information. Is the oven equipped with an induced flu, (electrically powered fan), how old is it, manual or electronic controls, are you resetting a manual safety or does it restart on its own. Without knowing more the best I can tell you is there are some common problems with furnaces and ovens, and basic troubleshooting procedures to follow.

First if you resetting a manual safety attempt to determine if the safety is defective or if there is an actual problem. You can check the temperature rating on the safety and attempt to duplicate that temperature , then check the safeties function , many of the simpler safeties are inexpensive just replace it. Many devices are equipped with a high limit safety if the oven's primary thermostat fails to shut it down the safety prevents dangerously high temperatures, check the temperature setting on the safety , then check the temperature the oven shuts down with a accurate thermometer. If your device is equipped with a induced flu make sure that fan motor is operating correctly. These are just some basic troubleshooting if you can provide some more information I may be able to provide more specific suggestions.

Just a quick note on safety, it is perfectly acceptable to momentarily bypass a safety to test ,never operate the equipment with its design safety features disable, there may be an intermittent problem that you don't see that is causing the safety to trip so leave whatever piece of equipment down until you can replace the safety, if you suspect that it is causing the problem.

Agree with you. the safety features are installed to protect your system and most likely, your lives. But there are also times when these features break down. Did you have an additional equipment? Are allyour parameters still the same when you first operated your system?

Although still not advisable, you can test your system with the safety features off. But only momentarily to check if your system is working well. But be ready to turn off the system or the valves manually if in case accident arises. And since you'd be playing with fire, do have a fire extinguisher beside you.

Somebody care to tell me what is off topic with 1

I agree Garth, very strange. I have no idea why 5 people set it to off topic!!!!

Would the brave 5 step forward please and say why they marked it "Off Topic"?

That would exactly explain why we see Off Topic score 5 so often......that is not good....

Ahh I see, that devious mouse jumping up and down on boxes to close to each other gave myself an uppercut.