I just bought a new (old) house and it is heated by a whole house hydronic radiant floor system. Our home inspector found a few small issues that need to be addressed, but there was one big unknown. It appears that the system has an overflow line that goes directly to the sewer line, but has no trap. I would assume this means that sewer gases are getting into my basement. Is this normal and/or the right way to install an overflow for a system like this?

Here are links to pics...

Full system: [drive.google.com]
Zoom/highlight of overflow: [drive.google.com]

That is NOT an 'overflow' pipe.

It is a code required 'funnel' (air gap 'built' into RPZ) fed drain from an Reduced Pressure Zone Backflow Prevention Device.


While it is acceptable for it to 'spit' occasionally, it should NOT discharge unless there is a (hopefully temporary) back pressure into the potable water supply.

Its purpose is to PREVENT a backflow of the hydronic water into the potable water.

It is located before the (automatic) feeder to the hydronic system.

The inline 'soft check' check valve AFTER the RPZ should prevent the 'spitting'.

HOWEVER, to answer your question:

the line probably does not, nor should it, connect directly to the sewer

adding a trap will be problematic if in fact it does connect directly, but, you would smell the stench QUICKLY if the sewer had a 'hole to atmosphere'

(said line 'generally' terminates juuuust above a floor drain)


OVERALL IMPRESSION OF SYSTEM: first class installation

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"Measure Twice & Cut Once" - Retired U.A. Local 1 & 638



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bern, i agree.

to add to your post..

the only time one of those expensive back flow valves is required is if there is anti-freeze in the system.
other wise a standard boiler type double check valve is fine and alot less troublesome.

jmartens, if you look in about the center of your whole system picture you will see 2 blue/green mixing valves.

those are used to control the temperature of the water going into the floor circuits.
there are thermometers on each circuit for you to read and you can by turning the blue knob raise or lower the water temperature. very useful in spring or fall when you only want about 100DEG going to the circuits. this prevents the rooms from getting too hot. BUT in the dead of winter you may want 140DEG water going to the floors.

you can play with this yourself if you are so inclined or just set them to a mid-range of 125DEG and for get about them.
invest in an inexpensive infrared heat gun and check your floor temperatures. you are looking for 85 - 90 DEG consistently.

BTW, i've put a few dozen systems in and everyone loves them. very comfortable .

[www.amazon.com]

Thank you both for your help! Regarding the connection to sewer, the inspector did a sewer scope and can see where the heating system punches into the sewer line, so does appear they did that. That said, sounds like a trap is not necessary nor the right thing to do?

The heating system may not 'punch into' the sewer ..... period.

A properly trapped and vented drain point needs to be established.

A floor drain needs to be installed.

The pipe from the RPZ may terminate juuust above said floor drain.

Since said pipe will no longer be connected to the sewer (but merely drain into a properly trapped floor drain) said pipe does NOT need a trap.

==============================================

"Measure Twice & Cut Once" - Retired U.A. Local 1 & 638

Sorry for my poor use of terminology, I am far from an expert, heck I am barely even a basic homeowner! The image link below is why I say "punch into the sewer line." The image is from the sewer scope during home inspection, and the location of what the inspector called ABS pipe is right below where the copper pipe goes into the basement floor.

[drive.google.com]

Where the copper drain goes into the floor there is a REMOVABLE cover.

My 'guess' is that the copper will 'lift out' from said cover allowing the cover to be removed for inspection.

In any event you NEED to inspect, or have inspected, where and how the copper connects, if it actually connects ..... there may actually BE a trap, or, it may simply 'drip' into the dirt.

OR


it all works ... there is no smell ... don't worry be happy

==============================================

"Measure Twice & Cut Once" - Retired U.A. Local 1 & 638

There are dangerous sewer gases that are odorless and colorless. They can make you sick or worse.

from Google:

"People can smell the “rotten egg” odor of hydrogen sulfide at low concentrations in air. However, with continuous low-level expo- sure, or at high concentrations, a person loses his/her ability to smell the gas even though it is still present (olfactory fatigue)."

My question is if this RPZ does release water how much and how long?
Could this drain be dumped into a laundry stand pipe?



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