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1. Note Humidifier Control setting and turn dial to the “OFF” position.
2. Turn off water supply.
3. Press the tabs in the latches on the top and bottom of front cover (1) and pull cover off
base with both hands. Set aside.
4. Carefully pull the plastic feed tube (2) out of the distribution tray (5) at the top of the
Water Panel evaporator assembly (4). Pull this assembly out by grasping at top and
tipping out.
5. Remove the distribution tray (5) from the water panel evaporator assembly by lifting
straight up from the scale control insert (8). Lightly scrape out any calcium deposits and
clean the “V” notches (6) but do not scrape off the granular coating from the bottom.
This textured surface helps ensure even water flow for maximum performance. See page
3 if removed.
6. Slide the Water Panel evaporator (7) out from the Scale Control Insert (8). Clean the
insert frame of calcium deposits with a putty knife. Inspect Water Panel evaporator
(Stock No. 35 for Model 600) and substitute a new Genuine Aprilaire Water Panel if
necessary. Slide the Water Panel back into the scale control insert with the colored spot
up and snap the distribution tray back into place.
7. Re-install the Water Panel evaporator assembly into the unit by fitting its drain into the
round receptacle at the base of the unit. Push the assembly in at the top against the
beveled tabs that will hold it in place. Push the end of the feed tube back firmly into the
distribution tray and replace the front cover.
8. Remove the drain hose (9) from the bottom of the unit and 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. Turn on the water supply.
10. Check system operation:
Humidifier Control
: (Automatic or Manual) Check system operation and reset change
water panel indicator by setting the knob to “Test/Reset”. With furnace blower operating
and furnace calling for heat, humidifier will operate for one minute. DO NOT LEAVE IN
TEST MODE AS HUMIDIFIER WILL NOT OPERATE.
11. Set Humidifier Control to its original position.
MAINTENANCE INSTRUCTIONS for
APRILAIRE HUMIDIFIER MODEL 600
CAUTION! Sudden operation may cause personal injury or
property damage. Turn Humidifier Control to “off” or
lowest setting before servicing.
1. Front Cover
2. Feed Tube
3. Integral Damper
4. Water Panel
Evaporator
Assembly
5. Distribution Tray
6. “V” Notches
7. Water Panel
8. Scale Control
Insert
9. Drain Hose
MODEL 600