# Another tankless question



## Plumber26 (Nov 10, 2010)

tim250f said:


> I will be soon hooking up a new tankless water heater in my new utility room. The unit I'm installing has a condensate drain tube that attaches to the base of the flue. My question is where should this line be drained? Can it be somehow tapped into existing plumbing? Or could it be tied into the pressure release drain piping?


 
Depending on how it's vented, you may not need to drain it anywhere. Read the directions. Most of the time if you vent it directly outdoors, the condensation will drain out sufficiently without use of the drain. On the Rinnai, you don't have to connect the drain unless the vent goes vertical more than 5'. But it will need to be drained to outside. Not connected to existing plumbing, not tapped into the T&P. NOTHING can share a drain with the T&P. If you want to let it drain into a laundry sink, that would be ok.


----------



## immeraufdemhund (Nov 17, 2010)

either. it's really only useful when it's cold outside. If it's a utility room though you might be able to run it to a floor drain or to a sink, but if that is too un-sightly than just tap into either one of those options.


----------



## tim250f (Oct 30, 2010)

Venting will be vertically about 4-5'. The unit is a Rheem RTG-84-DVN. I'm in south Louisiana so we don't get very cold for long. May not be a lot of condensation.


----------



## fabrk8r (Feb 12, 2010)

tim250f said:


> May not be a lot of condensation.


The condensate is a byproduct of the burning of NG and has nothing to do with outside temperature. You will typically get about 3/4 gallon of condensate water from burning 100,000 Btu worth of NG.

As Plumber26 said, if you are able to use a short enough concentric vent and pitch it to the outside you won't need a drain in the vent. The installation instructions will specify the details. 

And, as also mentioned, draining the condensate into a laundry sink or floor drain is okay. There are several other options for the drain, including tying it into your furnace condensate line if you have a 90% or higher AFUE furnace, or simply using a condensate pump.


----------



## tim250f (Oct 30, 2010)

So would it be acceptable to set up a stand pipe similar to a washer drain that I can drain the condensate?


----------



## immeraufdemhund (Nov 17, 2010)

If i understand the question correctly than your answer is yes, but make sure you put a P-trap in unless you want the awesome smell of sewer.


----------



## Michael Thomas (Jan 27, 2008)

One possible source of guidance are requirements as for A/C condensate drains discharging at the interior - discharge to an indirect waste receptor, no direct tap into the DWV plumbing.


----------



## moopey (Sep 14, 2010)

if your furnace or water heater is in the same room as the standpipe for your washer, you can drain the condensate into a condensate pump and run a 3/8"-1/2" plastic hose up and over to the washer drain. Thats what I did with my lennox furnace.

I intend to add a tankless water heater soon and will run the condensate from that to the pump I already have.


----------



## tim250f (Oct 30, 2010)

Michael Thomas said:


> One possible source of guidance are requirements as for A/C condensate drains discharging at the interior - discharge to an indirect waste receptor, no direct tap into the DWV plumbing.


What exactly is meant by an indirect waste receptor?


----------



## Ltnicks (Nov 9, 2010)

indirect waste is piping that does not connect directly to the drain system.

this piping can direct the flow to a drain


----------

