Aprilaire 448 - Manual (Page 16)

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1. Note humidistat or control setting and turn dial to the “OFF” position.
2. Disconnect electrical power and turn off water supply.
3. Unlatch humidifier cover assembly (1) from base assembly (2) at the bottom of the
cover, lift, and set aside.
4. Pull out the evaporative assembly (3) by grasping at the top and tipping out.
5. Remove the black distribution tray (4) from the evaporative assembly (3) by unsnap-
ping the white plastic holding strips from the tabs at the end of the tray. Lightly scrape
out any calcium deposits and clean the “V” notches (5) but do not scrape off the
granular coating from the bottom. This textured surface helps ensure even water
flow for maximum performance.
6. Slide the Water Panel evaporator (6) out from the white plastic Scale Control Insert (7).
Clean the Scale Control Insert by twisting and flexing it to loosen the calcium
deposits or use a putty knife. Inspect the Water Panel evaporator (Stock No. 35) and
replace with a new Genuine Aprilaire Water Panel if necessary. Slide the Water Panel
evaporator back into the scale control insert with the red colored spot up and snap the
black distribution tray (4) back into place.
7. Re-install the evaporative assembly (3) into the base assembly (2). Push the evaporative
assembly (3) in at the top between the retaining ribs that hold the assembly in place in
a vertical position.
8. Remove the drain hose (8) from the bottom of the unit. Bend and flex it to loosen the
internal calcium deposits. Then flush it with water under pressure and slip it back onto
the drain fitting.
9. Reinstall cover assembly (1) by hooking at the top of the base assembly (2) and
latching at the bottom.
10. Reconnect electrical power (9) and turn on the water supply.
11. Check system operation:
Humidifier Control: (Automatic or Manual) Check system operation by set-
ting the knob to “Test.” With furnace blower operating and furnace calling
for heat, humidifier will operate for one minute.
12. Set Humidifier or control to its original position.
MAINTENANCE INSTRUCTIONS
for
APRILAIRE HUMIDIFIER MODEL 700
WARNING! 120 volts may cause serious injury from electrical shock. Disconnect
power and shut off water supply before servicing.
1. Front Cover
2. Base
3. Water Panel
4. Distribution Tray
5. ”V” Notches
6. Water Panel
7. Scale Control Insert
8. Drain Hose
9. Power Cord
MODEL 700