Aprilaire 220 Service Manual page 17

INDIVIDUAL UNIT SERVICE—MODELS 445, 445A & 448
WARNING: 1. 120 VOLTS may cause serious injury from electrical shock. Disconnect
power and shut off water supply before servicing or troubleshooting
this unit.
2. Rotating or electrical components may cause serious injury from con-
tact. Keep hands and face clear when checking operation.
I. LACK OF HUMIDITY
●
Check The Home — See Pages 2 and 3.
●
Check Furnace Operation — See Page 3.
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Check The Humidity Control — See Page 4.
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General Maintenance — See Pages 4 and 5.
1. WATER SUPPLY PROBLEMS
a. Disconnect electrical power. Remove the motor board cover. Lubricate self-align-
ing motor bearings at the yellow hole on top and inside the yellow mark on the side of
the motor. After lubrication, carefully remove reservoir and pump cap. Remove any
deposits present in the pump column, impeller area or pump cap. Clean out pump
cap outlet. Hold shaft at impeller and rotate slowly while working shaft up and down.
Check operation.
b. Water level in reservoir should be 1/2" from top of black reservoir liner. If necessary,
bend float arm up slightly to adjust water level.
c. Position the impeller properly in the center of the pump cap. The impeller must have
the black marking up towards the motor. (Fig. 1)
d. Open water outlet in the pump cap with 5/32" drill bit. (Fig. 1)
e. Remove feed tube. Flex to remove deposits and flush with water under pressure.
Reattach feed tube and remove any sharp bends.
f. Check operation. If motor does not operate, check for pump motor cooling fan
obstructions. Pump motor cooling fan must not be pushed too far down on shaft or it
will obstruct shaft rotation. If motor still does not operate, replace motor.
2. AIR FLOW — Be sure the damper in the duct between the two plenums is open! Air
Flow is based on a 0.2 total static pressure difference between the supply and return
plenums. The static pressure can be determined with a U-Tube Manometer calibrated
in inches of water. Adjust the damper to obtain proper air flow at pressures greater
than 0.2 inches of water.
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