TPRV line and condensate line marriage

[ccarrington]

I have a quick question. I found a home with a TPRV line tee’d into the AC system condensate drain. Both lines enter a concrete poured slab after this connection, and neither line has an observable termination. The AC (and TPRV line) are clogged up somewhere below the pad….so if the TPRV tries to vent, all the water will go out the Tee to the furnace and either into the evaporator drain, or out the open top of the condensate line Tee. Also there is no pan, or pan drain on the water heater. This house just had a new hot water installed, and they told the lady that it was all up to code now…after the new heater was installed. The furnace and hot water heater are on an 18” elevated platform in the middle of the home in a utility room. If the water heater started leaking, damage would occur to the home (sheetrock and carpet) due to lack of the pan.

Most homes in this area are a poured slab (central Texas), and so I was wondering if it was acceptable to run the TPRV line (as its own line) up into the attic, and then down and out the back side of the home to term 6” above grade. I know that you are not suppose to run TPRV lines “up hill,” but the present installation is by far the greater evil, 2 Tees, and one tee has an open end like all condensate lines normally have.

The present installation will result in a hot water geyser in the furnace evaporator, or all over the front of the furnace at the open Tee… What should I recommend to the client? Did the Plumbers who installed the new hot water heater screw this lady, and should it be plumbed more safely, and a pan added. Also can you plumb a hot water pan drain into a condensate drain line? …Or should all three lines be separate and individual? The home was built in 1981.

[Jeffrey R. Pope]

The TPR discharge is required to be independent of all other discharge systems. It cannot share the condensate drain line of the FAU.

Originally Posted by ccarrington

. . . so I was wondering if it was acceptable to run the TPRV line (as its own line) up into the attic, and then down and out the back side of the home to term 6” above grade.

As you stated, it cannot run uphill either.

The IRC allows for the discharge to drain into the water heater over-flow pan. That is probably the easiest solution.

[ccarrington]

That is what I thought, but there is no pan installed on this unit, and so I was wondering if they could Tee the AC condensate discharge line into the pan drain line… the house is on a slab foundation, and there is no way to “add” additional below grade drain lines to this existing structure. There is only one ¾ drain line available for all three items… Condensate, HWH pan, and TPRV line… and the HWH and Furnace are both located in the middle of the home, so a pipe can’t be run out laterally through a wall, or down under the slab.

Should this be treated like a basement situation where there is no floor drain, and have some sort to indirect waste receptor installed with (output pump) to pump waste water up and out of the facility?

[David P. Valley]

First of all, you don't need TPR valve going into a drain. When the TPR valve leaks, you want your client to actually see this happening. This should be installed so that it is 6" from the floor.

The W/H pan drain line is there for emergency only. It will allow a water heater to seep into this drain if a leak occurs. There should be no other drain lines going into this W/H drain.

As for the condensate drain line, you can recommend that a condensate pump be installed to carry this condensate to the exterior.