Aprilaire 300 Owner's Manual page 18

REQUIRED MAINTENANCE INSTRUCTIONS
APRILAIRE HUMIDIFIER MODELS 500, 500M, 600 & 600M
SUDDEN OPERATION MAY CAUSE PERSONAL INJURY OR PROPERTY DAMAGE.
Turn the humidifier control to OFF or lowest setting before servicing.
A. Front Cover
B. Feed Tube
C. Bypass Damper
D. Water Panel Evaporative
Assembly
E. Distribution Tray
F. "V" Notches
G. Water Panel
H. Scale Control
Insert
I. Drain Line
1. Note humidifier control set point and turn dial to the OFF position.
2. Turn off water supply. Turn the bypass damper (C) to the SUMMER position.
3. Press the tabs in the latches on the top and bottom of front cover (A) and pull cover
off base with both hands. Set aside.
4. Carefully pull the plastic feed tube (B) out of the distribution tray (E) at the top of the
Water Panel evaporative assembly (D). Pull this assembly out by grasping at top and
tipping out.
5. Unsnap the distribution tray (E) from the scale control insert (H). Lightly scrape out or
brush off any mineral deposits, being careful not to stretch or loosen the synthetic
fabric liner. Soaking the tray in vinegar or a lime-removing agent is helpful when
trying to remove stubborn mineral deposits.
6. Slide the Water Panel (G) out from the scale control insert (H) and dispose of the
Water Panel. Clean the scale control insert of mineral deposits. Replace the Water
Panel (Water Panel 35 for Models 600 & 600M and Water Panel 10 for Models 500 &
500M) with a new genuine AprilAire Water Panel. Slide the Water Panel back into the
scale control insert with the colored spot up and snap the distribution tray (E) back
into place.
7. Inspect the plastic feed tube (B) by gently flexing it and looking for cracks or signs of
wear. Replace tube if it is cracked, brittle, or has been damaged.
8. Reinstall the Water Panel evaporative assembly (D) into the humidifier by fitting its
drain into the round receptacle at the base of the humidifier. Push the assembly in
at the top until it snaps into place. Push the end of the feed tube back firmly into the
distribution tray and replace the front cover.
9. Remove the drain line (I) from the bottom of the humidifier. If applicable, flex it to
loosen any mineral deposits or blockage. Then flush it with water under pressure. If it
does not properly clear, replace it. Slip drain line back onto the drain fitting. Make sure
the drain line has a constant downward slope and is not flattened or blocked.
10. Turn on the water supply. Return bypass damper to appropriate position.
11. Check system operation:
Manual Humidifier Control (Models 500M & 600M): With the HVAC system fan
operating, turn up humidifier control and check system operation.
Digital Humidifier Control (Models 500 & 600): (Automatic or Manual mode) Check
system operation and reset Change Water Panel indicator by setting the knob
to Test/Reset. With HVAC system fan operating and thermostat calling for heat,
humidifier will operate for one minute. DO NOT LEAVE IN TEST MODE AS HUMIDIFIER WILL
NOT OPERATE.
12. Set humidifier control dial to its original set point.
18
CAUTION
A
D
E
F
G
C
I
H
B
90-1076