Models 110 & 112 - Aprilaire 220 Service Manual

INDIVIDUAL UNIT SERVICE—MODELS 110 & 112
WARNING: 1. 120 VOLTS may cause serious injury from electrical shock. Disconnect
power and shut off water supply before servicing or troubleshooting
these units.
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.
●
Check The Humidity Control — See Page 4.
●
General Maintenance — See Pages 4 and 5.
draw new air into the Water Panel evaporator. In a situation like this, install 6" dividers
between the intake and discharge of the air flow as shown in the above diagram. This will
eliminate the possibility of recirculating air that is already humidified.
2. ELECTRICAL COMPONENTS — There are two electrical circuits in the Models 110- 112:
a 24 volt control circuit and a 120 volt power circuit. Failure of any electrical components in
the humidifier may result in a lack of humidity or if stuck in the operating position could
result in excess humidity. All components should be tested in place before removal making
sure all electrical connections are secure and there are no breaks in the service.
Old Style – Up to Serial # 484,805 (Model 110); 410,760 (Model 112)
a. Disconnect electrical power and check humidistat switch contacts and all wiring connections.
b. If both the motor and solenoid are not operating, the trouble may be in the relay. Disconnect
electrical power and insert a relay that is known to function and check.
c. If motor and solenoid still won't function, disconnect power to the furnace and replace the
transformer.
d. If either the motor or solenoid valve is not operating and the other is operating, the relay trans-
former and humidistat can be eliminated as a source of trouble. Disconnect electrical power
and replace the motor or solenoid valve whichever is not working.
120 VAC
1. AIR FLOW — Disconnect electrical power and turn off
water supply. Remove unit from plenum and remove upper
housing. With hands and face clear, reconnect electrical
power. If the fan blade is not rotating and the motor shaft is,
disconnect electrical power and secure the blade on the
shaft. When the blade is in the proper position, 1/3 of the
blade extends thru the opening in the shroud towards the
motor and 2/3 is thru the shroud towards the Water Panel.
In some unusual situations, there may be a particular air
movement thru the plenum that makes it difficult for the fan to
APRILAIRE HUMIDIFIER
WATER
VALVE
FAN
MOTOR
FURNACE
BLOWER
MOTOR
GREEN
WHITE
120 VAC
BLACK
RELAY 4012 (Internal) - 4 wires
BRACKET
24 VAC
TRANSFORMER
- 22 -
GROUND
HUMIDISTAT