Model 550 - Aprilaire 550 Owner's Manual

MAINTENANCE INSTRUCTIONS for
APRILAIRE HUMIDIFIER MODEL 550
CAUTION! Sudden operation may cause personal injury or
property damage. Turn Humidistat to "off" or lowest setting
before servicing.
1
1. Note Humidistat setting and turn dial
to the "OFF" position.
2. At the side of the unit opposite the airflow duct pull front cover (1) off holding with both
hands and set aside.
3. Carefully pull the plastic feed tube (2) out of the nozzle (3) at the top of the Water Panel
evaporative assembly (4). Pull this assembly out by grasping at top and tipping out.
4. Remove the distribution tray (5) from the Water Panel evaporative assembly by
unsnapping the plastic ends of the Scale Control Insert (8), from the tabs at the end of
the tray. Lightly scrape any calcium deposits out of the "V" notches (6), but do not
scrape the granular coating from the bottom of the tray. This textured surface helps
ensure even water flow for maximum performance. If the granular coating has been
removed, place several drops of liquid dish soap on the distribution tray and clean
thoroughly. This will only need to be done once.
5. Slide the Water Panel evaporator (7) out from the Scale Control Insert (8). Clean the
insert frame by twisting and flexing it to loosen the calcium deposits, or use a putty
knife. Inspect the Water Panel evaporator (Stock No. 10 for Model 550) and substitute a
new one if necessary. Slide the pad back into the insert frame with color mark up and
snap the distributor tray back into place.
6. Re-install the Water Panel evaporative 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
nozzle and replace the front cover.
7. 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.
8. Turn up Humidistat and check unit operation.
3 5 6
7
9
2
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4
8
1. Front Cover
2. Feed Tube
3. Nozzle
4. Water Panel
Evaporative
Assembly
5. Distribution Tray
6. "V" Notches
7. Water Panel
8. Scale Control Insert
9. Drain Hose