The fan on our radon system is working but the red oil level in the "u" is level so there is no suction for some reason. It's been very cold here lately (some Temps below zero) but I'm not sure if the pipe is frozen with condensation or what is going on with it. One weird thing is that now the basement intermittently smells like sewer gas. This same thing happened over the summer when we turned off the radon system fan to try and figure out how much energy it was using. The smell stopped when we turned the fan back on. Can anyone tell me why it would do this? It's Saturday and the place that installed it doesn't open until Monday. I don't want my family to have to live with this intermittent horrible stench for the next day or so if there is something we can do about it in the meantime. On a side note, we noticed the smell coming up through the heater vents and the heater has a drain tube going directly into the big drain pipe in the basement. Is there any way the smell could be coming from that??

Yes. The furnace condensate drain should never be piped directly into the drain stack without a p-trap and air gap. Somewhere you have a dry trap or untrapped connection that is letting in sewer gas. As for a fan on a radon system, I have never seen it. All the systems I have seen are sealed with a manometer attached. I suppose they are passive systems. I don't do anything with radon or radon reduction systems so I am ignorant of their construction. [www.epa.gov]

Thank you. I thought that was kind of odd. I'll have to double check again but it looks like the tube goes straight up then over along the ceiling then down into the stack. The weird thing is that it's only smelled this awful when the radon system was not on. They had to seal both floor drains when installing it and I'm wondering if there is a pressure back up from the system not properly venting. I'm just hoping the vent pipe had some frozen condensation that will melt and all will be smelling better. My biggest worry is that all the plumbing and piping is messed up.

why in the world would the radon installers block up your floor drains?
those drains tied into your sewer have absolutely nothing to do with radon.
if there is moisture blocking your radon vent then the installers did not provide a condensate drip tee to collect the moisture.
personally, i clasify radon and global warming in the scam folder..

From what I've read about them, they are supposed to seal the sump pump opening to create a vacuum for the passive system to work but we are on a hill so we don't have one. It's just the 2 floor drains. The whole set up down there has me a bit perplexed. I'm not sure who to even call out for the smell right now and it's more than a bit frustrating. I've run every water fixture/faucet we have our make sure it isn't a just dry p trap (that's the first thing I did). My husband is going to call the radon installer tomorrow to have them come take a look and I'm trying to figure out if it was installed wrong somehow and creating havoc in the process. *sigh* I can definitely think of better ways to spend the weekend lol.

the condensate drain from your furnace / ac should NOT tie directly into the sanitary piping

PERIOD

it MUST discharge via an 'air gap' either:

into a trap (similar to a washer)

or

into a floor drain

IMO: the radon fan was extracting the odor via a negative pressure in the basement

even after fixing the radon issue you must STILL fix the condensate drain

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

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

Ah OK. That makes sense. I'll have to talk to the company that installed it on Monday. They have some sort of box in front of the furnace which has the tube coming out, doing a loop, then straight up to the ceiling, across and down directly into the stack. It was just installed a few years ago so I may report them if it turns out they did it wrong.

if the tube has a loop in it, there is no way a smell can come back as long as the tube has water in it.look elsewhere for the source of the smell...

Smoke testing the vent system would be the fastest way of finding out where the problem is located.

or peppermint oil down the stack.

I really appreciate all the help with this! the loop looked dry and all I could see in the tube was droplets of condensation. I don't have any way to do a smoke test but would I just put oil right in the stack by removing a pipe? Or can I just dump it down the sink that's closest to it? The smell was pretty strong by the furnace when it was running. (I'm sure it wasn't natural gas though...it definitely has the rotten egg toilet smell.) It hasn't happened yet today (thankfully) and I want to figure this out so it doesn't happen again.



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the peppermint test must be done from outside.
the box at the furmace is a condensate pump.
if the loop is dry then the possibility of the smell coming from it is likely.
dump some water into the condensate pump to make it cycle. that should fill the loop. see if that stops the smell.

Where would I pour it into?

I just looked again and the tube has water in it now. The radon system is also working again as well and the smell is gone so I'm back to being clueless until when/if it happens again.