Hey Martin, you assume correct. There was no floor drain.
Anthony as the water heater builds pressure the TPR releases water and stops, its a slow cycle. The same thing for the temperature cycle it opens and as cold water enters the heater the TPR closes. I’ve never seen a valve discharge wide open with the exception of forcing the valve to open when testing. The folks who write and amend code books put a lot of thought into their content and have thought of concerns you have mentioned. Drain lines are sized in accordance. Great question as TPR questions come up often on this forum.
2 Likes
I see. Thanks Martin, from the video’s I’ve watched on the InterNachi classes, Kenton failed to state that. They make it seem as it would explode open as the pressure inside the tank is so intense. In addition, I have never observed one in action. Thank you for the clarification. Makes more sense now.
1 Like
Good information here Anthony.
1 Like
Gray is da man.
1 Like
The discharge piping stops at the air gap. The p trap is in a drain pipe not the discharge pipe.
1 Like
I have a sister in law that is remodeling and has electric hot water tank on 2ed floor bathroom in a closet. What is the best way to satisfy all the tpr and drain pan requrements? Even the master plumbers in Arkansas do not know!
1 Like
Enjoy the music! 
2 Likes
I don’t know if this is the latest but see 605.5.10. I learned early on never call your company expert…,professional…I don’t like the phrase master plumber. Time to find a regular plumber. You would be surprised how much the newer guys know that are fresh out of apprentice school.
1 Like
Drain pipe also needs to be identified as a “drain pipe” that drains somewhere other than the sanitary sewer. Once The 3/4” male adapter is screwed into the TPR valve, that is where the discharge pipe begins and local drain codes come into play. Makes a huge difference such as p-traps, vents for p-traps. A “drain pipe” that is part of the sanitary sewer is a different animal all together.
1 Like