Aprilaire 440 Humidifier User Manual


 
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MODELS 768-760
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 insert frame by twisting and flexing it to loosen the calcium deposits or use
a putty knife. Replace Water Panel evaporator annually with a new Water Panel evapo-
rator (Stock No. 35). 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:
Manual Humidistat:
Turn up humidistat to highest setting and make sure the
furnace blower is operating. Humidifier will operate if RH is less than 50%.
Automatic Humidifier Control: Check system operation by setting the knob
to Test. With furnace blower operating and furnace calling for heat,
humidifier will operate for one minute.
12.
Set humidistat or control to its original position
.
MAINTENANCE INSTRUCTIONS
for
APRILAIRE HUMIDIFIER MODELS 768-760
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. Evaporative
Assembly
4. Distribution Tray
5. V Notches
6. Water Panel
7. Scale Control Insert
8. Drain Hose
9. Power Cord
4
5
6
7
8
9
1
2
3