Aprilaire 800 Series - Water Chemistry

6
Moisture in the duct
1. Verify absorption distance for voltage and amperage setting. Many factors contribute to
absorption distance. See table 2 in the Installation & Maintenance Instructions.
a. Verify plenum temperature, air velocity and humidity level
b. Ensure control is properly mounted
c. Install a high humidity switch in series with the humidifier and humidistat to prevent over
humidification in the duct.
2. If the steam dispersion tube is mounted on a horizontal run, verify the dispersion tube is low in the
duct, at least 4” from the top of the duct. On vertical runs center the dispersion tube on the duct.
3. Verify the steam hose slopes down and away from the duct toward the humidifier or a tee and
drain trap. A minimum slope of 2” per foot is recommended.
4. Verify the steam dispersion tube is mounted with the “Tubelets
TM
” facing up.
Water Chemistry
1. The minerals contained in the supply water dictate how the humidifier operates and plays a large
role in the life of the canister. Water quality and mineral content varies dramatically across the
country, following the guidelines below will help determine what water type to use.
a. Softened water, whether with sodium chloride or potassium chloride will allow the
humidifier to come to full capacity faster, and the canister will last longer. There will be
more frequent drain cycles and a higher potential for foaming both resulting in more water
usage.
b. Hard water minerals, calcium and Magnesium, combine with bicarbonate and carbonate
ions and drop out of the water when heated, this reduces the ions in the water causing a
slower start up and scale formation in the canister reducing canister life. Using hard water
will drain less than soft water; this uses less water and energy and gives a more constant
steam output.
2. Check with the local water utility to see if orthophosphates or polyphosphates are used. These
chemicals are used to control corrosion and sequester lead in piping systems. Phosphates will
insulate the electrodes in the canister causing the canister life to be significantly degraded. Do not
install the humidifier is phosphate levels are above 1ppm (or 1mg/L).