The best way I know to illiwstrate how to install a T&P line on a water heater is to show one that is not installed correctly.
There are two problems with this instation. First the termination point is more than 6 " above the floor. The second is that it is not a smooth pipe. The t&p line must slope down continuously to the termination point. It is preferable to make the termination point outside where it can't damage baseboard or drywall.
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This is excellent information for Arizona buyers and sellers. I frequently see flex instead of ridgid. It's the easy way out without having to sweat the pipe.
Recommended feature.
Thanks Leolinda - they don't exactly give out instructions on how to install water heaters at the hardware store.