T&P drain tee to A/C

[homnspector]

As I understand it, the relief valve drain line should run separately from any other piping. I am wondering if the check valve makes this acceptable.

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[homnspector]

Dang, what happened to my picture?

Anyway, there was an air conditioner CDL with a nice trap then a brass or bronze check valve then a tee to the T&P relief valve drain line. A/C was added later and I guess they were trying to avoid running an additional line.

[hausdok]

You might be trying to post too large a photo. If you've got windows, go to powertoys for windows and downsize the free image resizing tool there and then try again. Also make sure that there aren't any blanks and special symbols in the photo and that you've saved it in an acceptable format such as .jpg.

OT - OF!!!

M.

[Scottpat]

You want the T&P discharge to be visible, that is why the code says it needs to discharge to a visible location. If it is hidden in a condensation drain line, then you can't see it and you would not know it is leaking.

[Brandon Chew]

Here's the relevant section from the 2000 IRC:

§RP2803.6.1 Requirements of discharge pipe. The outlet of a pressure relief valve, temperature relief valve or combination thereof, shall not be directly connected to the drainage system. The discharge from the relief valve shall be piped full size separately to the outside of the building or to an indirect waste receptor located inside the building. In areas subject to freezing, the relief valve shall discharge through an air gap into an indirect waste receptor located within a heated space. The discharge shall be installed in a manner that does not cause personal injury or property damage and that is readily observable by the building occupants. The discharge from a relief valve shall not be trapped. The diameter of the discharge piping shall not be less than the diameter of the relief valve outlet. The discharge pipe shall be installed so as to drain by gravity flow and shall terminate atmospherically not more than 6 inches (152 mm) above the floor. The end of the discharge pipe shall not be threaded.

The code is specific that the "discharge from the relief valve shall be piped full size separately" and that it can only go to one of two places -- either outside the building or to an indirect waste receptor inside the building. There are not any exceptions or additional provisions. An additional requirement is that the discharge needs to be "readily observable by the building occupants." This is so the building occupants can see and become aware the the TPR valve is discharging. If the air conditioning condensate drain line and the TPR drain line are connected together, and there is water coming out of the end of the pipe most of the time (AC condensate), the homeowner might not know or notice when the TPR releases or starts leaking.

P.S. - Dang, that Scott P is quick! I had a half-finished reply cued up, left to put on a fresh pot of coffee, and then came back to proof-read & post.