Water Heaters - T&P Valve Question

I recently replaced my gas water heater in the garage. The old T&P valve was soldered to a copper pipe that runs into the wall (no idea where it goes). In the "emergency" I simply hooked the new T&P valve to a run of PVC and ran it out towards the garage door.

Question is - can I leave that old T&P pipe as is with the rag stuffed :o into it or do I have to cap it off? If the latter, how?

Any thoughts?

The T&P valve pipe should be ok as is. They normally are run to the outside of the house or under it if there is a crawl space. This is merely to keep the hot water from flooding your house incase of a failure or leak.

You should check the codes in your area. Some codes require that the operating T&P valve be piped outside the house. If you were ever to sell the home you would have to change it beforehand.

Walk around outside your home and see if you can find the other end of this pipe. It should be 3/4 inch pipe. If you have a crawl space it may be piped under the house. Will just be an open pipe coming out of the floor.

Good luck and reply back if you have further questions

Ah thanks...

I'll have to check the crawlspace next time I'm down there, that's where it would be since it's on an inside garage wall.

If I had to hook the new one to the old pipe, would it have to be all solid copper or could I juse some PVC to the copper (or is that dependent on code as well)?

You can check your local codes but I do not believe they will let you run PVC. The diameter of the discharge cannot be reduced however you could probably sweat a brass union into the line for a quicker disconnection. They may also let you use CPVC which is rated for hot water but I believe the diameter is smaller than copper. Good luck and reply back with any questions you may have.

Hello: bjm

If the existing copper pipe is already installed, it may be safe to assume it meets code. May not be so and may be worth checking into. Seattle, like many states, may have revised some codes to update the older standards, etc. But not so likely for only a drain run off line.

The existing PVC drain line from the T/P valve can be connected to the already installed copper section via a transition fitting. Check with a local privately owned hardware store. Not a BIG Box mass marketer.

Usually and most likely, the local hardware store owners and/or floor sales help know what the plumbers use. If plumbers are using a transition fitting, than you can reasonably assume doing so also meets code.

The drain line only carries hot water, if any comes out of the T/P valve. Therefore, PVC used in a non enclosed or confined section, should be just fine.

Thanks all, I'll dig around and see what I can find...

Washington and Oregon Use the UPC code, Wa will have a revised code as we have in Or, UPC says T&P discharge must be of a material used for Hot Water and the same size as the discharge 3/4" i.e. Copper, CPVC, Galvanized, Pex.

PVC is not rated for hot water there for can not be used on the T&P Discharge.

UPC states if the water heater is in a garage which the grade has slope towards door, then discharge line can be piped to about 6" off the floor and does not need to go to the outside of building.

Now I do not have the revised copy Wa code book, I can only speculate how it might be, check with code there. Call the plumbing inspector, he will be more the happy to tell you for sure what is and what is not.

Where could I get a hold of a code book?

There is a BuildingBook Tech Store you can order the 2003 UPC code book, you will also need to get the Washington Amendments to the 2003 Code.

Order Form For Wa State Code Book (http://www.buildingtechbooks.com/pdf/plumbing.pdf)

Perfect, thanks...