# New HVAC, bad smell present when AC runs



## Soinuht (10 mo ago)

Homeowner here, had a new HEIL installed last June when the old unit quit. Never had an issue with odor with the old unit. No odor through the summer while the AC ran more frequently (we live in the southeast). Once we hit the in between season where it was cool enough in the overnight for the heat to run and then the AC may cut on in the afternoon, we noticed a pungent, sour smell ONLY when the AC runs. At times, a yeasty bread smell when the heat runs. Tech came out and installed an oxiclean product in the unit. We are in March now and with the AC starting back up, the smell is back...just as bad if not worse. Tech came out again, states the coil is dry, and they did not smell anything inside the unit, but is going to install an air purifier, free of charge. 

Can anyone shed some light on what the root cause could be?


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## Kangaroogod (Dec 6, 2011)

Google dirty sock syndrome. Maybe your issue 

Sent from my SM-N960U using Tapatalk


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## Steven123cool (Mar 2, 2021)

Soinuht said:


> Homeowner here, had a new HEIL installed last June when the old unit quit. Never had an issue with odor with the old unit. No odor through the summer while the AC ran more frequently (we live in the southeast). Once we hit the in between season where it was cool enough in the overnight for the heat to run and then the AC may cut on in the afternoon, we noticed a pungent, sour smell ONLY when the AC runs. At times, a yeasty bread smell when the heat runs. Tech came out and installed an oxiclean product in the unit. We are in March now and with the AC starting back up, the smell is back...just as bad if not worse. Tech came out again, states the coil is dry, and they did not smell anything inside the unit, but is going to install an air purifier, free of charge.
> 
> Can anyone shed some light on what the root cause could be?


Some where in the duct you are condensating and accumulating dust on it .From the hot duct to cool duct during your afternoon AC; then the heat kicks on and bakes it just enough to make it rotten and the process begins again. Probobly condensing at both change overs


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