Model 800 Canister Steam Humidifier with Digital Humidifier Control

Aprilaire 800 Location and Dimension

When choosing a location for the dispersion tube you must consider location in duct, elevation with respect to the humidifier, and distance from humidifier to dispersion tube.

The preferred location for the dispersion tube is in a supply duct to maximize air absorption of moisture. The dispensing tube should be higher than the humidifier with a slope at least 2" per foot from the humidifier. The maximum recommendation length of the steam hose is 6 feet, to prevent reduction of capacity due to condensation.

Electrical Power Wiring

The Model 800 Steam Humidifier is shipped from the factory wired for 240 VAC operation, but it can operate on 120, 208 or 240 VAC. If using 120V or 208V, move the black/white jumper wire attached to L1 tab on the power terminal block to the proper tab on the transformer terminal block.

Knock-outs for power wiring and low voltage control circuit wiring are located on the top of the humidifier.

• 208v Wiring Diagram
• 240v Wiring Diagram
• Digital Control Wiring
• 120v Wiring Diagram

How Electrode Steam Humidifier Works

Electrode steam humidifier operates by energizing two electrode extended into a canister of water. The current flowing between the electrodes and resistance of the water to the electric current heats the water.

Minerals that are naturally found in water cause the water to be electrically conductive. Water conductivity is measured in micro Siemens per centimeter (uS/cm). Generally the higher mineral content the higher the conductivity.

That being said water that is considered “hard”, potable or softened water have a higher conductivity and works well for the humidifier. Low hardness water or less conductive water will take longer to reach capacity. A tea spoon of bicarbonate of soda or salt can be added into the filling cup on start-up to speed up steam production. Demineralized or reversed osmosis water should not be used with electrode steam humidifier.

As water boils into steam minerals are left behind. The remaining mineral will increase the conductivity of the water but also cause deposit onto the submerged portions of the electrodes, rendering those areas ineffective. As this occurs, the water level will rise to expose uncoated electrode surface. The internal controller senses water level and measures the current flowing between the electrodes to determine when the canister needs replacement.