Septic fumes in house

[Richard]

sigh... and I think I know why.

Scenario: Our air handler system is in basement (which will be finished). It's technically in the garage.

The drain pan has a drain that goes to a sump pump and this pump is drained/routed with the HVAC lines, up to the ceiling, along the ceiling and finally outdoors. Once it gets outdoors, I have it merged into a simple drain line to take it away from the house.

We have frequent power outages and when those happen, the water in the exit line comes back INTO the sump and gets dumped onto the floor

So...

This past summer, I was redoing the utility room and one thing I wanted to do was take the vertical drain away from the sump pump and make it gravity fed so I'd "never" have any wet floor issues again.

OK.. so I made a drain, snaked it around the room, brought it to this location and now, the drain from the pan, is connected directly to my plumbing.

I even have a "P" trap in it HOWEVER, it seems the volume of water in the trap isn't a whole lot (3/4" line) and over time will evaporate allowing the air handler unit to pull some fumes backwards from the septic system and very nicely, blow it throughout the house.

I've since come to know/understand that the typical way this is done is to have a drain (say, in the floor, which will NOT work for me) and have the air handler drain DRIP into said drain, having an 'air break' between the two, instead of having it hard plumbed like mine is.

I'm not sure how to word the above so I hope that makes sense.

Bottom line... mine is currently hard plumbed to the actual pan under the air handler.

Knowing I might someday need/want to work in here, I DID install some threaded ...uh... unions! that's the word.

So I've got a threaded union here... any merit in removing part of this line, cutting a section out and inserting into said section, a 1-way valve?

Would a 1-way valve have enough 'stopping power' to prevent gasses from working their way back during less humid times?

During warm/humid months, this is NOT an issue but I'm learning that during the less humid times of the year... it seems it IS an issue and I'd really like to fix this and JUST as strongly, I'd like to STAY AWAY from the electric sump pump I have so I can totally eliminate water puddles during times of no power.


Any thoughts??

 

[kenmac]

You need to seal your air handler . & or duct. You have a return air leak that you shouldn't have. Buy u a condensate pump for your a/c to drain into .

 

[JRobyn]

Shouldn't the air handler drain have a slight POSITIVE pressure? Or if it's a simple drain pan (like an overflow pan under a furnace/AC evap coil), there should be no pressure at all, either positive or suction. I'm not following how this is happening.

How about adding a small branch line just upstream of the p-trap with a removable cap that you can use to periodically fill up the trap?

- Jay

 

[sawdust_maker]

sigh... and I think I know why.
So I've got a threaded union here... any merit in removing part of this line, cutting a section out and inserting into said section, a 1-way valve?

Would a 1-way valve have enough 'stopping power' to prevent gasses from working their way back during less humid times?

A one way valve is spring loaded. It will not allow water to just drain through it without some pressure behind it.

John

 

[RonMar]

What John said... the gravity water from the drip pan most likley won't drain thru a check valve.

Short term, you could just dump some water into the drain pan occasionally to keep the "P" trap from drying out. If that works, as with a large pressure differential, the airhandler could draw sewer gas back thru a filled "P" trap, and If you have a source of water near by, you could run a small water line to it, like that used for a referigerator ice maker(ice maker installation kit) and have it constantly drip water into the air handler condensate pan to keep the trap saturated. We had this problem with the air handler drains all the time on the first ship I was on. Short of plumbing in a small sump with pump and a check valve for the condensate drip pan, the plummed water supply is the easies idea that quickly comes to mind.

 

[dooleysm]

Vegetable oil will last alot longer in your trap than water. That's what I put in the floor drain in my basement shower that gets used 1 or 2 times per year.

 

[shaley]

How about drain the condensate into a tub and then sump pump with a check valve in the tub. Isn't this the issue anyway, the vertical leg drains back when the power goes out. Put the check at the beginning of that line.

 

[shaley]

The only other remote posibility that could cause this, and I saw it on our loacal news at 11, were it caused a deadly septic gas explosion, is having the hot water line hooked to the toliet. But Iv'e never heard of anyone else doing that.

 

[podagrower]

In commercial buildings, the plumbers often use a "trap primer". Usually a 1/2 inch line with a special valve that "drips" water into the drain to prevent drying out.
I had a problem with an air handler sucking air through the drain once. It was just a 1" pipe with a shallow bend in it. I used a heat gun and made a deeper bend in the pipe and it solved my issue. Perhaps you could make a deeper P trap.

 

[tony123]

I'm in a new house, and am trying to resolve some septic smells myself. Our guest shower gets used about once a month. The P trap seems to be evaporating in less than a months time. I'm surprised, as I've been in other houses where it takes a year or more.

I've also got a case where my hot water heater drip pan is plumbed to drain into a sewer pipe with a P trap (that includes one of those slow drip valves). It does the same thing, but will evaporate in like 2 weeks.

I wonder if deeper P traps would help in these cases? worth a try I suppose. Although, in the case of the hot water heater I think it may actually be suction that is pulling water out of the P trap.