This week, at three inspections in a row, I found TPR drain lines that were improperly installed. By improperly installed, I mean that they were routed up. In some cases there were other defects as well -- the TPR drain was routed into flex tubing, a no no, or the line terminated in the crawl space or too high off the ground outside.

In one case the homeowner wanted to argue that this is not a problem because pressurized water is involved so I did not know what I was talking about. He is wrong. This arrangement is not allowed in any professional plumbing standards and it violates any plumbing code that is published.

What the fellow says, if you know nothing about it, makes sense. You envision water coming out of the TPR valve under high pressure and as steam. The fact is, this valve may discharge water periodically, as part of it doing it's job. That is especially true if there is what is called a closed system and if there is no thermal expansion tank. These valves are factory set at 150 PSI. I have seen municipal water pressure to homes that was too high -- over 130 PSI. 80 PSI is the top of the normal range and that is considered to be too high by most plumbers. In high pressure situations like that, where the water heater is under stress to begin with, I have seen these valves discharge water. And it is NOTHING like a steamy situation. In the average situation, as the tank heats and pressure hits 150 PSI, anywhere from a few drops to a cup or so of water comes out. That relieves the pressure for awhile, then it may build up again and discharge more. The water coming out the drain is NOT superheated. It is the same temperature as the hot water being used in the house. About the only way the discharge water will be superheated is if the thermostat should stick on. The valve is relieving pressure, not temperature. Sometimes the two coincide but not always.

If the valve is routed up, and any amount from a few drops to a cup of water flows out, as you can see above in the photo, that small amount of water would stay in the pipe -- up tight to the valve. Overtime, that can lead to corrosion, damage and failure of the valve. When that happens, then you have a big safety issue.

Sometimes homeowners, who know a little bit, but not nearly as much as they think they know, can be their own worst enemies.

Thanks for stopping by,

Steven L. Smith