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I'm a homeowner that has gone through 2 HVAC technicians in troubleshooting a condensate smell issue in my house with no luck. I'm looking for some insights on what to even try next to troubleshoot the problem. Any advice would be helpful. Thanks in advance.
About a month or so ago, I started to noticing a strong acidic smell in 2nd floor laundry room's drain pipe, the same type of odor that is being emitted from my furnace exhaust pipe. I tracked the problem down to the furnace located in my 3rd floor that is pumping the furnace water condensate down to the drain in my 2nd floor laundry room.
I called a top rated HVAC company to come look at the problem, and the guy practically did nothing but tell me to seal off the drain opening in my laundry room.
I called a second HVAC company and they helped me install a pump and neutralizer for the 3rd floor furnace. That took the smell away from the laundry room but that smell is now in the 3rd floor where condensate water collects next to the furnace.
So a couple of things that was already investigated.
* The HVAC unit is about 1.5 years old hooked up to Propane heating.
* There's no CO leak detected just the smell.
* There doesn't appear to be crack in the heat exchange.
* The smell that is emitted from this HVAC unit on the 3rd floor does not exist in my basement HVAC unit and both were installed around the same time.
I was also attached some pictures of the condensate pump / neutralizer. You can see that within a 2 weeks of installation, the neutralizer balls are all turning black. Not sure if that's normal or not.
The other picture shows that there's this grey rubber tube that connects the flue gas exhaust pipe directly to my condensate box.
​So I'm guessing that whatever is not being vented out the flue gas exhaust is trickling back the pipe and into my condenser via that grey tube and that's what's causing the smell. So the 2nd HVAC guy just recommended that disconnect that tube and plug the holes which will then force the unvented liquids back into the inducer motor. I'm hesitant to do this as I'm not a HVAC guy and my downstairs HVAC is setup the same way and doesn't have this problem.
So my questions are.
Why is the upstairs HVAC producing this obnoxious smell through its exhaust and the basement HVAC exhaust does not? Is this a combustion problem where the flue gas isn't burning properly.
Do you think I can remove that grey tube connecting the flue gas exhaust pipe to the condenser? Do you think that will help? .
Is the furnace condensate really suppose the smell? If so, is there a way to get rid of that smell?
I'm just trying to figure how what to ask when I hire a 3rd HVAC company.
Question from user Fieto9122 at hvacadvice at reddit.com.
Based on the information you provided, there are several possible causes of the odor from your HVAC unit. It's important to note that without an on-site inspection, it can be challenging to pinpoint the exact cause of the problem. However, here are some potential causes and suggestions that you can discuss with your third HVAC company:
Drain line issue: The smell could be originating from the drain line that connects the furnace to the condensate pump. If the drain line is clogged or improperly installed, it can cause condensate to accumulate and create an unpleasant odor. Your second HVAC technician tried to solve this issue by installing a pump and neutralizer, but it appears that the problem has not been entirely resolved. You may want to ask the third HVAC company to check the drain line for any clogs or leaks and ensure that it's correctly installed.
Improper combustion: The odor could be caused by improper combustion in the furnace. The furnace may not be burning fuel efficiently, which can cause incomplete combustion and produce unpleasant odors. It's also possible that there could be a blockage in the flue, which can cause exhaust gases to enter the condensate system. Your second HVAC technician suggested disconnecting the tube that connects the flue gas exhaust pipe to the condenser, which may help if the issue is caused by improper combustion. However, it's essential to note that this solution may not work if there is an underlying problem with the furnace's combustion process.
Bacterial growth: The condensate that collects in the condensate pump can create a breeding ground for bacteria, which can produce a foul odor. Your second HVAC technician installed a neutralizer to address this issue, but if the neutralizer balls are turning black quickly, it may indicate that the neutralizer is not functioning correctly. You can ask the third HVAC technician to check the neutralizer to ensure it's working correctly and replace it if necessary.
Other factors: There may be other factors that are contributing to the odor, such as a dirty air filter or ductwork issues. It's worth asking the third HVAC company to check these factors as well.
In summary, there are several potential causes of the odor from your HVAC unit, and it may require further investigation by a qualified technician to pinpoint the exact cause. You can discuss the potential causes mentioned above with the third HVAC company to help them diagnose and resolve the issue.