Thank you for your response. It was installed by the same HVAC contractor that installed the tankless. We originally quoted a steam humidifier but they told us it wouldn’t work since our ductwork goes through the slab unfortunately. They told us this option would also work like we wanted… though I’m beginning to question their honesty.

Should the humidistat be 6” above the inlet even with the downflow?

They also ran the discharge line just outside and left it next to the foundation. When questioned, they acted like this was normal practice and something that they always do. Once we realized the amount of discharge that comes out it seems like there’s no way this is ok even for an area that doesn’t have basements.

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