Replacement Canister for Aprilair 800 Humidifiers

For best performance, Aprilaire recommends that you change the canister in your humidifier once per year.

• Turn off the power using the on/off button on the front of the humidifier panel.
• The 'Drain' icon will now begin flashing; this light indicates that water is being drained from the unit. Once the light stops flashing, you can disconnect the power to your humidifier.


• Using a screwdriver, remove the panel on the front of your humidifier.
• Inside, you'll locate the canister you'll be replacing.
• First, disconnect the wires from the canister.
• Second, disconnect the hose clamp and remove the thick black dispersion tube that's attached to the canister.
• You'll now be able to remove the canister from the unit.
• Each new canister will include a new o-ring; your old o-ring might in the drain assembly and needs to be removed.
• Insert the new canister bottom first, ensuring the labels face toward you.
• Reattach the dispersion tube and hose clamp; reconnect the wires.
• Replace the panel, reconnect the power and turn the unit on.