Thread: Pressure releif Valve discharge

Need help please. On an inspection today with a slab on grade home. The PRV discharge pipe terminated roughly 8" below grade and coming through the side of the foundation. I thought that it had to terminate above grade but no higher that 6" off of the ground. Thanks in advance.

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Originally Posted by Jeffrey Black

The PRV discharge pipe terminated roughly 8" below grade and coming through the side of the foundation.

Jeffery,

I'm having a problem visualizing what you are describing, and how you are seeing what I am visualizing.

The termination is "roughly 8" below grade", how can you see that?

Or do you mean that the discharge pipe goes down, through the foundation wall below grade, then turns back up and terminates above grade?

I thought that it had to terminate above grade but no higher that 6" off of the ground.

The "old way" was to run it outdoors and terminate it above grade. The manufacturer wanted 'at least' 6" above grade and the code wanted 'within' 6" above grade, making it 'right at' 6" above grade.

That was the "old way".

The new way requires the discharge line to terminate in the same room or space as the water heater. The discharge line can terminate above a floor drain through an air gap or into an indirect waste receptor through an air gap, either way, though, it needs to terminate at an air gap in the same room or space as the water heater, and the waste is then taken to the sewer system or to the outside.

Jeffrey,

If that pipe is down inside a drain, then you have a cross-connection possibility which is a health safety hazard of its own. It needs to terminate 4-6" above grade.

Originally Posted by Grant Jones

Jeffrey,

If that pipe is down inside a drain, then you have a cross-connection possibility which is a health safety hazard of its own. It needs to terminate 4-6" above grade.

A cross connection is really not that likely (Yes, it is possible but not probable) due to the height of the valve and the pressure in the tank. The main concern is being able to view any discharge and to protect the occupants of the home from any steam that might discharge.