Navien Water Heater Oily Fluid

[jjonas (Jeffrey Jonas)]

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Navien Tankless Hot Water Heater has brown oily fluid inside

I recently inspected a Navien hot water heater. I believe this unit is 6-7 years old. When I opened up the panel there was a brown oily fluid on the bottom of the heat exchanger and on the intake. These are both made of some kind of black plastic. It appears to be condensate but I am not sure why it would be oily. From what I saw online, Navien states that plastic does not contain any oil that would cause this. I can’t find any info on this at this point. Has anyone seen this and know what the c…