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MattR757, HVAC Technician
Category: HVAC
Satisfied Customers: 59
Experience:  18+ Years experience in residential and commercial HVAC service and repair
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Had an Aprilaire 800 installed. Sounded like the right unit

Customer Question

Had an Aprilaire 800 installed. Sounded like the right unit for my size house here in Colorado. Previous model 400? really did not do much was on the forced air side going into the heated furnace air. Seemed wrong to put water into the heat, Current problem is water runs out of the duct work and has rusted registers through the house.
JA: Did you double-check the thermostat's settings? And what about the filters?
Customer: Settings for furnace were as always. 68 night 70 day. And the filters electronically and is cleaned regularly, could it be that the steamer starts before the furnace up to heat and the duct work hot enough to prevent condensation. Could "injector" hose br to close to the T where the airflow is directed lateral into the main trunk? Should it be relocated to the return side??
JA: Do you plan on doing the work yourself?
Customer: NO WAY I fix teeth! Work was done by an HVAC tech with experience. Another HVAC friend made the previous suggestions,
JA: Anything else we should know to help you best?
Customer: Like whaT?
Submitted: 4 months ago.
Category: HVAC
Expert:  MattR757 replied 4 months ago.

I'm not sure if I can offer a solution, but I'd like ti weigh in with a couple of observations:

The Aprilaire 400 is the smallest bypass type humidifier that aprilaire makes and is suitable for homes up to 4000 square feet - The model 800 is a steam humidifier that should be suitable for homes up to 6200 square feet so the humidity output is much higher.

The installation of the 800 is pretty specific - The dispersion tube has to be located in a straight section of duct upstream of any bends or obstructions, (definitely not in the return side) the unit has to be level and the tubing has to have slope away from the dispersion point - All of this is to keep the water from condensing and dripping into the ductwork.

It's possible that the dispersion point is located too close to the unit or in an air current eddy, causing condensation (humidity not being carried down the duct with the airstream) - It's also quite possible that the unit is producing too much humidity for the airflow - The 800 can be configured with a downstream humidity sensor that acts as a high humidity limit to keep the supply air from over-humidifying.

These are the installation guidelines that explain some of the details :