Aprilaire 10-112 Technical specifications

- 10 -
1. Note Humidistat setting and turn dial to the “off” position.
2. Disconnect electrical power and turn off water supply.
3. Disconnect: a) 120 volt electrical service. b) Copper water supply line (1)
& feed tube (2). c) Drain line. d) 24 volt leads.
4. Turn two swing locks (3), one at either side of lower housing off humidifier flange.
5. Lift humidifier straight up until bottom of unit clears lip of lower housing.
Pull unit out at bottom, lower and remove.
6. Slide off three closure clips (4 & 5) that holds 2 halves of unit together.
7. Remove upper half of unit.
8. Remove Water Panel evaporator and Scale Control Insert. Remove Water Panel
evaporator from Insert and clean Insert by flexing or using putty knife. Inspect
Water Panel evaporator and replace with a new Water Panel evaporator
(Stock No. 10 for Model 110 and Stock No. 12 for Model 112), with colored spot up.
9. Remove the plastic drain hose from the bottom of the unit and flex it to loosen the
internal calcium deposits. Then flush it with water under pressure and slip it back
onto the black drain fitting. Make sure the drain hose has a constant downward
slope and is not flattened or blocked.
10. Remove the water distribution pan cover (6) and clean “V” openings in water
distribution section but do not scrape off granular coating from bottom. This helps
to insure proper, even water flow for maximum performance. See page 2 if removed.
11. Oil motor with 2 drops of SAE 20 oil in oil holes at each end of motor housing.
12. IMPORTANT: When installing Scale Control Insert and Water Panel evaporator in
the humidifier, the Insert spout must discharge directly into unit drain.
13. Reassemble unit, position feed tube in compression fitting, tighten compression
nuts and secure copper feed tube to upper housing with feed tube clamp.
14. In reverse order, complete steps 1 and 4 to reinstall your humidifier, and check
unit operation.
3
4
6
1
2
4
5
MODELS 110-112
MAINTENANCE INSTRUCTIONS for
APRILAIRE HUMIDIFIER MODELS 110-112
WARNING! 120 volts may cause serious injury from electrical shock.
Disconnect power and shut off water supply before servicing.
1. Water Supply Line
2. Feed Tube
3. Swing Locks
4. Closure Clip
5. Closure Clip
6. Distribution Pan Cover

- 11 -
1. Note Humidistat setting and turn dial to the “off” position.
2. Turn off water supply and turn down humidistat.
3. Remove three “Z” clips (1) that hold top half of unit to furnace plenum.
4. Slide off four closure clips (2 & 3) that hold two halves of unit together.
5. Loosen compression fitting (4) on copper feed tube (6) and remove.
6. Remove top screw holding sheet metal elbow to humidifier.
7. Remove top half of unit (lift straight up).
8. Remove the water distribution pan cover (5) and clean “V” openings in water
distribution section but do not scrape off granular coating from bottom. This helps
to insure proper, even water flow for maximum performance. See page 3 if removed.
9. Remove Water Panel evaporator and Scale Control Insert. Remove Water Panel
evaporator from Insert and clean Insert by flexing or using putty knife. Inspect
Water Panel evaporator and replace with a new Water Panel evaporator
(Stock No. 10 for Model 220 and Stock No. 12 for Model 224), with colored spot up.
10. Remove the drain hose from the bottom of the unit and flex it to loosen the internal
calcium deposits. Then flush it with water under pressure and slip it back onto the
black drain fitting. Make sure the drain hose has a constant downward slope and is
not flattened or blocked.
11. IMPORTANT: When installing the Scale Control Insert and Water Panel evaporator
in the humidifier, the Insert spout must discharge directly into unit drain.
12. Reassemble unit, position feed tube in compression fitting, tighten compression
nuts and secure copper feed tube to upper housing with feed tube clamp. Attach to
furnace plenum.
13. Turn on water supply, turn up humidistat and check unit operation.
MAINTENANCE INSTRUCTIONS for
APRILAIRE HUMIDIFIER MODELS 220-224
CAUTION! Sudden operation may cause personal injury or property
damage. Turn humidistat to “off” or lowest setting before servicing.
1. “Z” Clip
2. Closure Clip
3. Closure Clip
4. Compression Fitting
5. Distribution Pan Cover
6. Feed Tube
33
4
5
6
1
1
22
MODELS 220-224
1

- 12 -
1. Note Humidistat setting and turn dial to the “off” position.
2. Disconnect electrical power and turn off water supply.
3. Remove screws of the inlet grille (1). The grille can now be removed from the metal
housing (8).
4. Lift the complete plastic framed evaporative section out of the humidifier housing.
5. To remove the distribution tray (2) from evaporative assembly (9), push down on tray
and pull out on white plastic frame (Scale Control Insert) (3). To clean the “V”
openings of the tray, it will be necessary to gently pry the distribution tray cover (4)
from the tray. Follow instructions below depending upon the type of distribution tray
in your humidifier.
For trays with a synthetic fabric liner: 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.
For trays with granular coating: Do not scrape off the granular coating, but lightly
scrape out any mineral deposits and clean the “V” notches.This textured surface
helps ensure even water flow for maximum performance. See page 3 if removed.
6. Remove Water Panel evaporator (5) from the Scale Control Insert (3). Scrape the
Insert with a putty knife or similar tool and flush clean with water. Install new Water
Panel evaporator (Stock No. 35). Snap plastic cover into tray and tray into Scale
Control Insert.
7. Inspect the plastic feed tube by gently flexing it and looking for cracks or signs of
wear. Replace tube if it is cracked, brittle or has been damaged.
8. Remove the drain hose from the bottom of the unit and flex it to loosen the internal
calcium deposits. Then flush it with water under pressure and slip it back onto the
black drain fitting (6). Make sure the drain hose has a constant downward slope and
is not flattened or blocked.
9. Re-install complete plastic framed evaporative section and intake grille.
10. Reconnect electrical power.
11. Turn on water supply and check unit operation.
MAINTENANCE INSTRUCTIONS for
APRILAIRE HUMIDIFIER MODELS 350-360
WARNING! 120 volts may cause serious injury from electrical shock.
Disconnect power and shut off water supply before servicing.
1. Inlet Grille
2. Distribution Tray
3. Scale Control Insert
4. Distribution Tray Cover
5. Water Panel
6. Drain Spud
7. Power Cord
8. Metal Housing
9. Evaporative Assembly
3
4
5
6
7
8
9
1
2
MODELS 350-360

- 13 -
MAINTENANCE INSTRUCTIONS for
APRILAIRE HUMIDIFIER MODEL 440
CAUTION! Sudden operation
may cause personal injury or
property damage. Turn
humidistat to “off” or lowest
setting before servicing.
1. Note humidistat setting and turn
dial to the “Off” position.
2. Remove two aluminum knobs (1),
swing up and remove top cover (2)
from humidifier.
3. Place finger under plastic water
nozzle (3) at top of water
distribution tray (4). Lift up to pop
outlet loose from hole and notch in distribution tray.
4. Tip forward and lift the complete plastic framed
evaporative assembly out of the humidifier.
5. To remove plastic water distribution tray from evaporative
assembly, push down on pan and out on plastic frame
(Scale Control Insert). Follow instructions below depending
upon the type of distribution tray in your humidifier.
For trays with a synthetic fabric liner: 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.
For trays with granular coating: Do not scrape off the granular coating, but lightly
scrape out any mineral deposits and clean the “V” notches.This textured surface
helps ensure even water flow for maximum performance. See page 3 if removed.
6. Remove Water Panel evaporator from Scale Control Insert and clean Insert by
flexing or using putty knife. Inspect Water Panel evaporator (Stock No. 12) and
replace if necessary with colored spot up. Snap plastic water distribution tray back
in place.
7. For units with plastic feed tubes, inspect the tube 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 evaporative section in the humidifier with notch and hole in plastic water
distribution pan toward you. Pop nozzle fitting on end of feed tube into plastic water
distribution pan.
9. To reinstall top cover, hook back under lip of metal frame (5), drop in place and
tighten two aluminum knobs.
10. Remove drain hose and flush with water under pressure. Mineral deposits in hose
may be loosened by flexing hose.
11. Reattach drain hose. Make sure the drain hose has a constant downward slope
and is not flattened or blocked.
12. Turn humidistat to highest setting and make sure the furnace blower
is operating. Humidifier will operate if RH is less than 50%.
13. Set humidistat to its original position.
MODELS
440, 445 & 448
1. Cover Knob
2. Top Cover
3. Feed Nozzle
4. Distribution Tray
5. Metal Frame
3
4
5
1
2
1
MODEL 440

- 14 -
MAINTENANCE INSTRUCTIONS for
APRILAIRE HUMIDIFIER MODELS 445-448
WARNING! 120 volts may cause
serious injury from electrical
shock. Disconnect power and
shut off water supply before
servicing.
1. Note humidistat or Humidifier
Control setting and turn dial to the
“Off” position.
2. Disconnect electrical power and turn
off water supply.
3. Remove two aluminum knobs (1),
swing up and remove top cover (2)
from humidifier.
4. Place finger under plastic water nozzle (3) at top of water
distribution tray (4). Lift up to pop outlet loose from hole and
notch in distribution tray.
5. Tip forward and lift the complete plastic framed evaporative
section out of the humidifier.
6. To remove plastic water distribution tray from evaporative
section, push down on pan and out on plastic frame (Scale Control Insert). Follow
instructions below depending upon the type of distribution tray in your humidifier.
For trays with a synthetic fabric liner: 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.
For trays with granular coating: Do not scrape off the granular coating, but lightly
scrape out any mineral deposits and clean the “V” notches.This textured surface
helps ensure even water flow for maximum performance. See page 3 if removed.
7. Remove Water Panel evaporator and Scale Control Insert. Remove Water Panel
evaporator from Insert and clean insert by flexing or using putty knife. Inspect
Water Panel evaporator and replace with a new Water Panel evaporator, if
necessary, with colored spot up.
8. Re-install water distribution tray. Reinstall evaporative section in the humidifier,
with notch and hole in distribution tray toward you. Pop hose fitting on end of feed
tube into distribution tray.
9. See page 15 for reservoir and pump cleaning.
MODELS
440, 445 & 448
1. Cover Knob
2. Top Cover
3. Feed Nozzle
4. Distribution Tray
5. Metal Frame
3
4
5
1
2
1
MODELS 445-448

- 15 -
A. TO CLEAN RESERVOIR
1. Hold bottom of reservoir (IT IS FILLED
WITH WATER) and loosen retainer knob.
Carefully lower reservoir, disengaging
from metal frame.
2. Empty water, remove partition and
reservoir liner.
3. Clean or replace reservoir liner. Reinstall
partition in liner. To replace reservoir,
hook back of reservoir over lip of dark
metal frame and tighten knob.
B. TO CLEAN HOSE
1. Disconnect hose from pump and pull
hose up through hole.
2. Flex hose to loosen scale and flush clean
with a stream of water.
3. Clean nozzle at the same time.
C. TO CLEAN PUMP
1. Remove pump impellor cap (1) by
pushing down on projecting sides (2).
2. Clean scale from inside of cover and
impellor (3) with dull blade.
3. Clean flow control (4) in pump outlet with
5/32” bit.
4. Snap pump impellor cap (1) back in
place.
5. Pull water hose down through hole,
connect to pump, and attach nozzle into
water distribution tray.
D. TO CLEAN FLOAT
1. Clean scale off float (5) and arm
mechanism (6) with dull blade.
2. Work arm mechanism (6) up and down to
dislodge any scale buildup.
E. TO OIL MOTOR
1. Disconnect water line at valve inlet and
swing line free. Disconnect the
humidistat leads.
2. Remove the three screws from the
brown motor cover and remove.
3. Use two drops SAE 20 oil in the yellow
hole on top and inside the yellow mark
on the side of the motor.
F. TO REASSEMBLE
1. Replace motor cover.
2. To reinstall reservoir, hook back of
reservoir over lip of dark brown metal
frame and tighten knob.
3. Reconnect water at valve inlet.
4. To reinstall top cover, hook back under
lip of dark brown metal frame and tighten
two knobs.
5. Reconnect humidistat or control leads
and electrical power.
6. Turn on water supply and fill reservoir in
the fall.
7. Check unit operation.
8. Check system operation:
Manual Humidistat: Turn up humidistat to
highest setting and make sure the
furnace blower is operating. Humidifier
will operate if RH is less than 50%.
Humidifier Control: Check system
operation by setting the knob to “Test.”
With furnace blower operating and
furnace calling for heat, humidifier will
operate for one minute.
9. Set humidistat or Control to its original
position.
6
2
1
3
4
5
2
MODELS 445-448
MAINTENANCE INSTRUCTIONS for
MODELS 445-448 RESERVOIR PUMP SECTIONS
WARNING! 120 volts may cause serious injury from electrical shock.
Disconnect power and shut off water supply before servicing.
IMPORTANT: Clean and refill reservoir, hose, pump and float every
30 days during heating season.
1. Pump Impellor Cap
2. Cap Sides
3. Impellor
4. Cap Flow Control Opening
5. Float
6. Arm Mechanism

- 13 -
1. Note Humidistat setting and turn dial to the “OFF” position.
2. Turn offf water supply. Turn the integral bypass damper (10) to the SUMMER position.
3. At the side of the unit opposite the airflow duct pull front cover (1) off holding with both
hands and set aside.
4. Carefully pull the plastic feed tube (2) out of the nozzle (3) at the top of the Water Panel
evaporator assembly (4). Pull this assembly out by grasping at top and tipping out.
5. Unsnap the distribution tray from the scale control insert (8). Follow the instructions below
depending upon the type of distribution tray in your humidifier:
For trays with a synthetic fabric liner: 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.
For trays with granular coating: Do not scrape off the granular coating, but lightly scrape
out any mineral deposits and clean the “V” notches (6).This textured surface helps ensure
even water flow for maximum performance. See page 3 if removed.
6. 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. Replace the Water Panel
evaporator (Stock No. 10) and with a new Genuine Aprilaire Water Panel. Slide the pad
back into the insert frame with color mark up and snap the distributon tray back into place.
7. Inspect the plastic feed tube (2) by gently flexing it and looking for cracks or signs of wear.
Replace tube if it is cracked, brittle, or has been damaged.
8. Re-install the Water Panel evaporator assembly (4) 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 (2) back firmly into the
nozzle and replace the front cover.
9. Remove the drain hose (9) from the bottom of the unit and flex it to loosen any mineral
deposits or blockage. Then flush it with water under pressure and slip it back onto the
drain fitting. Make sure the drain hose has a constant downward slope and is not flattened
or blocked.
10. Turn on the water supply.
11. Check system operation:
Humidistat: With the furnace blower operating and the furnace calling for heat, turn up
Humidistat and check system operation .
12. Set Humidistat to its original position.
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. Front Cover
2. Feed Tube
3. Nozzle
4. Water Panel
Evaporator Assembly
5. Distribution Tray
6. ”V” Notches
7. Water Panel
8. Scale Control Insert
9. Drain Hose
10. Integral Bypass
Damper
7
56
8
9
1
2
34
10
MODEL 550

- 16 -
MODELS 558-560-568
1. Note humidistat or Humidifier Control setting and turn dial to the “OFF” position.
2. Turn off water supply.
3. At the side of the unit opposite the airflow duct pull front cover (1) off holding with both hands
and set aside.
4. 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.
5. Remove the plastic distribution tray (5) from the evaporative assembly by unsnapping the
plastic holding strips from the tabs at the end of the tray. Follow instructions below
depending upon the type of distribution tray in your humidifier.
For trays with a synthetic fabric liner: 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.
For trays with granular coating: Do not scrape off the granular coating, but lightly scrape out
any mineral deposits and clean the “V” notches.This textured surface helps ensure even
water flow for maximum performance. See page 3 if removed.
6. Slide the Water Panel evaporator (7) out from the plastic 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. 35 for Model 560) and substitute a new one if
necessary. Slide the pad back into the insert frame with the colored spot up and snap the
distributor tray back into place.
7. Inspect the plastic feed tube by gently flexing it and looking for cracks or signs of wear.
Replace tube if it is cracked, brittle, or has been damaged.
8. 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.
9. Remove the drain hose (9) from the bottom of the unit and flex it to loosen the internal mineral
deposits. Then flush it with water under pressure and slip it back onto the black drain fitting.
Make sure the drain hose has a constant downward slope and is not flattened or blocked.
10. Turn on water supply.
11. Check system operation:
Manual Humidistat: Turn up humidistat to highest setting and make sure the furnace blower
is operating. Humidifier will operate if RH is less than 50%.
Humidifier Control: Check system operation by setting the knob to “Test.” With furnace
blower operating and furnace calling for heat, humidifier will operate for one minute.
12. Set humidistat or Control to its original position.
MAINTENANCE INSTRUCTIONS for
APRILAIRE HUMIDIFIER MODELS 558-560-568
CAUTION! Sudden operation may cause personal injury or
property damage. Turn humidistat or control to “off” or lowest
setting before servicing.
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
7
56
8
9
1
2
34

- 17 -
1. Note humidistat or Humidifier Control setting and turn dial to the “OFF” position.
2. Disconnect electrical power and turn off water supply.
3. Unlatch humidifier cover assembly (1) from base assembly (2) at the bottom of the cover, lift, and
set aside.
4. Pull out the evaporative assembly (3) by grasping at the top and tipping out.
5. Remove the distribution tray (4) from the evaporative assembly (3) by unsnapping the plastic
holding strips from the tabs at the end of the tray. Follow instructions below depending upon the
type of distribution tray in your humidifier.
For trays with a synthetic fabric liner: 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.
For trays with granular coating: Do not scrape off the granular coating, but lightly scrape out any
mineral deposits and clean the “V” notches.This textured surface helps ensure even water flow
for maximum performance. See page 3 if removed.
6. Slide the Water Panel evaporator (6) out from the plastic scale control insert (7). Clean the insert
frame by twisting and flexing it to loosen the mineral deposits or use a putty knife. Replace Water
Panel evaporator annually with a new Water Panel evaporator (Stock No. 35). Slide the Water
Panel evaporator back into the scale control insert with the colored spot up and snap the
distribution tray (4) back into place.
7. Inspect the plastic feed tube by gently flexing it and looking for cracks or signs of wear. Replace
tube if it is cracked, brittle or has been damaged.
8. Re-install the evaporative assembly (3) into the base assembly (2). Push the evaporative assembly
(3) in at the top between the retaining ribs that hold the assembly in place in a vertical position.
9. Remove the drain hose (8) from the bottom of the unit. Flex it to loosen the internal mineral
deposits. Then flush it with water under pressure and slip it back onto the drain fitting. Make sure
the drain hose has a constant downward slope and is not flattened or blocked
10. Reinstall cover assembly (1) by hooking at the top of the base assembly (2) and latching at the
bottom.
11. Reconnect electrical power (9) and turn on the water supply.
12. Check system operation:
Manual Humidistat: Turn up humidistat to highest setting and make sure the furnace blower is
operating. Humidifier will operate if RH is less than 50%.
Humidifier Control: Check system operation by setting the knob to “Test.” With furnace blower
operating and furnace calling for heat, humidifier will operate for one minute.
13. Set humidistat or Humidifier Control to its original position.
4
5
6
7
8
9
1
2
3
MAINTENANCE INSTRUCTIONS for
APRILAIRE HUMIDIFIER MODELS 760-768
WARNING! 120 volts may cause serious injury from
electrical shock. Disconnect power and shut off water
supply before servicing.
1. Front Cover
2. Base
3. Evaporative
Assembly
4. Distribution Tray
5. ”V” Notches
6. Water Panel
7. Scale Control Insert
8. Drain Hose
9. Power Cord
MODELS 760-768