Plumbing/AC/Code/Sewer gas smell question

[LeeH]

Plumbing/AC/Code/Sewer gas smell question - Bet you weren't expecting that combo, now were you?

A week or so ago our condenser was replaced due to a leak. Since then, we've had a sewer gas smell in the house. One possibility I uncovered while reading on the subject is that our A/C condensate line drain runs down and ties into a sink drain, but on the back side of the trap. In other words, the drain is open to the sewer line.

The new condenser was a different configuration than the last one. I'm thinking that the smell is coming from sewer gas being sucked into the system from the drain.

Am I correct in thinking that their should be a trap in this line? Also, should the installer have removed the knock out to allow water to drain into the emergency pan? I thought this guy knew what he was doing, but now I'm wondering.

[porsche4life]

Yes there should be a trap in there. I'll defer to an expert on the other thing...

I'll bring my PVC tools when we do the water heater! Man, it's not your month!

[ossiblue]

I would agree that the drain is incorrectly connected and is allowing sewer gas to enter the house. There should be a trap between all exposed sewer lines and open house space.

[DerkPerk]

You are exactly right in your diagnosis. Should have been T'd into the tail piece of the sink drain.
I'm not one for removing the overflow plug unless it is piped to a obviously seen place.
Also a trap should be installed according to the manufacture design, most likely yes. You could get away from one ONLY if the condensate pan is on the positive pressure side of the blower but guessing that isn't the case because of the smell.
You could eliminate the smell by adding a trap next to the unit but it would have to stay primed or the smell will return. I also recommend changing the drain tie in.
Typical residential hack installer. Good luck.

[NY65912]

Condensate from AC always gets a p-trap.

[VincentVega]

Can you run the drain outside or into a utility sink? I had to redo a similar setup, as mentioned the trap needs to be full, not sure its possible unless you run the A/C year round.

[LeeH]

Originally Posted by VincentVega

Can you run the drain outside or into a utility sink? I had to redo a similar setup, as mentioned the trap needs to be full, not sure its possible unless you run the A/C year round.

So what's the answer? I can install a trap and fill with water, but seems like that little bit is going evaporate in just a couple of weeks. The air handler is in the attic. Could run the drain outside, but it would be sticking out the side of the house up about 10' off the ground.

[Cajundaddy]

I would either re-plumb under the sink or run the drain line outside. Either way will correct the problem. My HVAC unit is on the roof and the condensate line runs down into a rain gutter. It just needs to be gravity flow to a place that can handle significant water during your monsoon season.

[LeeH]

Hmm... I'm thinking this real issue is under the bathroom sink. The tailpiece is on the wrong side of the trap. This obviously wasn't caused by the a/c guy. If the tailpiece drained into the sink trap, would the connection in the attic still require its own trap?

[mfiazzo]

Put in a condensate pump and pump the condensate into the sink or outside. No need to cut into any drains. Condensate pump will cost you $50.00.

Still need a trap in the PVC so water does not get sucked back in.

Little GIANT 115-Volt Automatic Condensate Removal Pump-554401 - The Home Depot

[LeeH]

I don't understand the need for a pump when the air handler is in the attic.

As far as the lack of trap... As a licensed AC guy, should the tech who installed the coil and hooked up the pvc to the drain pan done something about the lack of trap?

[Cajundaddy]

Originally Posted by LeeH

Hmm... I'm thinking this real issue is under the bathroom sink. The tailpiece is on the wrong side of the trap. This obviously wasn't caused by the a/c guy. If the tailpiece drained into the sink trap, would the connection in the attic still require its own trap?

Post a pic of your under-sink plumbing. The re-plumb to correct this should be cheap and easy.

[BK911]

Is your unit draw through or blow through?

[look 171]

Originally Posted by porsche4life

Yes there should be a trap in there. I'll defer to an expert on the other thing...

I'll bring my PVC tools when we do the water heater! Man, it's not your month!

Siht man, you wanna to come to live in LA? My wife is a terrible cook, but I am more then happy to buy you all the beer and Pizza you want. Man's food. Do I get a month?

[look 171]

Originally Posted by LeeH

So what's the answer? I can install a trap and fill with water, but seems like that little bit is going evaporate in just a couple of weeks. The air handler is in the attic. Could run the drain outside, but it would be sticking out the side of the house up about 10' off the ground.

Don't do that. You will get all kind of water stain and mossy in winter. WEll, maybe not for you out there?

Get a pic of the set up under the sink and show where its plumbed into the drain. It's usually from a flex rubber hose Y into and above the p-trap.

[look 171]

Out here, there is no need for a trap for the drain coming from air handler. Maybe I and everybody fell asleep on the inspection?

[LeeH]

Originally Posted by look 171

Don't do that. You will get all kind of water stain and mossy in winter. WEll, maybe not for you out there?

Get a pic of the set up under the sink and show where its plumbed into the drain. It's usually from a flex rubber hose Y into and above the p-trap.

I'm thinking the drain on the last pan must have been on the positive side or we would have had the same problem. This one is clearly on the negative side. Explains why we've been waking up to a big stink as it's been cold here and the system has been running all night.

[mfiazzo]

The pump will pump the condensate directly outside, hence no need to cut into or have to worry about a drain line in the plumbing. If your plumbing backs up, it will back up into your A/C unit. I have seen this happen.

Also, may townships do not allow condensate to go into public sewers because of the high cost of sewage treatment.

[look 171]

Originally Posted by LeeH

I'm thinking the drain on the last pan must have been on the positive side or we would have had the same problem. This one is clearly on the negative side. Explains why we've been waking up to a big stink as it's been cold here and the system has been running all night.

It needs to feed into that white vertical pipe. I hate those bastards installers that don't care. Well, many of the don't understand how things really outside of their trade.

[LeeH]

Originally Posted by look 171

It needs to feed into that white vertical pipe. I hate those bastards installers that don't care. Well, many of the don't understand how things really outside of their trade.

It's possible that the contractor who remodeled the bathroom and installed the sink moved it. The sink is thick glass, and I remember them having issues making everything fit.

I'm also assuming that the condensate drain on the previous coil was on the positive side instead of the negative side. Otherwise, we'd have had this same issue long ago.