Connect drip pan drain line into T&P drain line?

I'm installing a new WH in the garage WH closet and must bring the installation up to code which means installing a drip pan and an expansion tank. I already have a 3/4" copper line for the T&P valve which goes through the exterior wall and drains outside.

I know the T&P drain line cannot go into the drip pan. That's not what I'm trying to do.

Per Code, can I "tee" the drip pan drain line into the vertical existing T&P drain line so I don't have to drill another hole in the exterior stone wainscoating? I would install a swing check valve on the drip pan drain line. Our town uses the 2003 UPC.

that is over kill

I dont know what code you use but
if you are installing a metal drip pan
its not a problem to drop the t+p valve into
that pan...


I do not see a problem with just putting a tee down the line
to catch the t+p valve,
I would not put a swing check valve in line of any
t+p valve...,,





I am sure that this will open up a grand and glorous debate
cause I am really not all that sure what is the final word on this
subject...

Picture better than my words

Thanks for the reply but I don't think I described the situation accurately. So I attached a bitmap. Can I tie in the drip pan drain into the existing T&P valve drain line with or without a swing check valve?

The city will inspect this.

When I dream of TPR valve extensions at night that are piped improperly, the following often appear next to ghostly images of Redwood or Terry. Then I wake up.

504.6 Requirements for discharge piping

The discharge piping serving a pressure relief valve, temperature relief valve or combination thereof shall:

1. Not be directly connected to the drainage system.
2. Discharge through an air gap located in the same room as the water heater.
3. Not be smaller than the diameter of the outlet of the valve served and shall discharge full size to the air gap.
4. Serve a single relief device and shall not connect to piping serving any other relief device or equipment.
5. Discharge to the floor, to an indirect waste receptor or to the outdoors. Where discharging to the outdoors in areas subject to freezing, discharge piping shall be first piped to an indirect waste receptor through an air gap located in a conditioned area.
6. Discharge in a manner that does not cause personal injury or structural damage.
7. Discharge to a termination point that is readily observable by the building occupants.
8. Not be trapped.
9. Be installed so as to flow by gravity.
10. Not terminate more than 6 inches (152 mm) above the floor or waste receptor.
11. Not have a threaded connection at the end of such piping.
12. Not have valves or tee fittings.
13. Be constructed of those materials listed in Section 605.4 or materials tested, rated and approved for such use in accordance with ASME A112.4.1.

So no, installation as in your picture would probably be a violation on many counts. But you could just discharge it in the pan like Mark said, with the 6 inch gap. That's why he's master and I am just a fictional character, who was once a home owner and never a senior member.

So, like this?

"But you could just discharge it in the pan like Mark said, with the 6 inch gap" So, assuming I have a 6 inch gap in the revised drawing, it's ok?

150 psi, 210 degree water splashing at 6 inches would definitely alert me to any issues! Thanks for your patience.

that should be ok

that looks ok to me, and is generally how
we always do them so the homeowner can see
if their are weeping issues...

We use the Oaty plastic pans, and I suppose that they are code here cause I see them all the time done this way..


the only thing better than the heavy duty plastic pans are the all metal ones..

somewhere out there is an inspector that is worried that the boiling hot water
will melt the Oaty Water heater pan....

I suppose the plastic pans are probably not code in some
areas of this country so I would suggest spend the extra money and
get the metal one