MAINTENANCE INSTRUCTIONS
for
APRILAIRE HUMIDIFIER MODEL 400
WARNING! 120 volts may cause serious injury from electrical shock. Disconnect power and shut off water supply 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/ Float Chamber
9.Overflow Hose
10.Float Cover
11.Float
12.Water Level Sensor Assembly
MODEL
400
1.Note humidistat or control setting and turn dial to the “Off” position.
2.Turn off water supply. Turn the damper (3) to the SUMMER position.
3.Press the tabs in the latches on the top and bottom of front cover (1) and pull cover off base with both hands.
4.Carefully pull the plastic feed tube (2) out of the distribution tray (5) at the top of the Water Panel evaporator assembly (4). Tip the water panel evaporator assembly forward and lift it out of the humidifier. Do not tip the water panel evaporator assembly more than needed to clear the housing to avoid
5.Unsnap the distribution tray from the scale control insert (8). Lightly scrape out any cal- cium deposits and clean the “V” notches (6) but do not scrape off the granular coating. This textured surface helps ensure even water flow for maximum performance. See page 2 if removed.
6.Slide the used water panel (7) out of the scale control insert/float chamber and dispose of the water panel. Inspect the overflow hose (9) to make sure it is open.
7.Remove the float cover (10) and inspect the floats (11) and float chamber for mineral
8.Slide a new Aprilaire no. 45 water panel into the scale control insert/float chamber. Snap the distribution tray back on the scale control insert.
9.Reinstall the water panel evaporator assembly into the humidifier. Take care not to
10.Push the end of the feed tube back firmly into the distribution tray. Reset the damper to desired position. Replace the front cover.
11.Turn on the water supply.
12.Reset humidistat control to its original position. Check operation.
MODEL 400
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