Aprilaire 500 series Installation Instructions

ATTENTION INSTALLER

Read this installation template before installing humidifier. Warranty
is void unless humidifier is installed by qualified heating and air
conditioning contractor due to possible misapplication of product.
This product must be installed in compliance with all local, state, and
federal codes. Proper humidification and humidity control require that
the home be constructed with local codes and good building practices.

WARNING

ELECTRICAL SHOCK HAZARD. Disconnect power to the
furnace before installing humidifier.
CAUTION
SHARP EDGES. Use care when cutting and handling ductwork.
HOT WATER CAN SCALD. Shut off hot water supply before
tapping into hot water supply.

NOTICE

FREEZING TEMPERATURES CAN BURST WATER PIPES.
• Do not install humidifier where freezing may occur.
CONDENSATION DAMAGE OR MOLD CAN OCCUR.
• Locate return duct mounted humidifier control at least 6"
upstream of humidifier, bypass duct connection, or fresh air
intake for accurate humidity sensing.
• Locate wall mount humidifier control in areas unaffected by
drafts or heat sources for accurate humidity sensing.
• Reduce the setting on the humidifier control if condensation
forms on windows or in unheated spaces.
EQUIPMENT DAMAGE MAY OCCUR.
• Do not install humidifier or bypass connection on the
furnace jacket.
• Do not connect the transformer to the blower motor wiring.
• Do not install the humidifier or bypass connection on a
plenum face at the blanked end of the cooling coil.
• If water pressure exceeds 125 psi, reduce water pressure
with devices allowed by local codes.
• Do not use water with temperature greater than 140°F.
• Do not install humidifier on systems with differential
pressure greater than 0.4 w.g. between the supply and
return plenums.
• When installing the humidifier control on the return duct
of a downflow furnace, ensure the blower continues to run
after a heat call is satisfied.
Model 500 Series Humidifier Template

SPECIFICATIONS

Humidifier Dimensions:
Width (including solenoid valve): 15-5/8"
Height (including drain spud): 13"
Depth: 10-1/4"
Bypass Duct Opening:
Plenum Opening:
9-1/2"W x 9-1/2"H
Water Feed Rate: 3 gph
Electrical Data: 24 VAC, 60 Hz, 0.5 Amp
Water Panel®: Model 10

INSTALLATION OPTIONS (LEFT HAND DISCHARGE SHOWN)

Aprilaire® Model 500 and 500M can be installed
on either the supply plenum or cold air return of
a forced air handling system with right hand or
left hand bypass duct connections. The humidifier
dimensions and serviceability must be considered
when selecting the best location for the humidifier.
Hot water is recommended (140°F max) to
provide maximum evaporative capacity. It is also
recommended when the Blower Activation Feature
is used with an Automatic Digital Humidifier Control,
or on a heat pump system. The humidifier functions
with cold, hot, softened, or unsoftened water.

PARTS LIST

1. Front Cover
2. Base
3.
Feed Tube
4.
Water Distribution Tray
5.
Water Panel®
6. Scale Control Insert
7. Integral Damper
8. Damper Handle
9. Drain Spud
10. Hole Plug
11. Nameplate
12.
Solenoid Valve
TEMPLATE MUST BE LEVEL

FURNISHED ITEMS

• Humidifier with built-in bypass damper
Return
• 24 VAC transformer
• Automatic Digital Humidifier Control and
Outdoor Temperature Sensor (Model 500 only)
6" diameter
• Manual Humidifier Control (Model 500M only)
• Humidifier Control Installation Instructions
• Saddle valve
• Humidifier Installation Template
Return
Supply
10
2
Floor Drain or
Condensate
Pump
7
8
9
Return

ITEMS NOT FURNISHED

• Mounting screws (sheet metal screws)
• Water supply line (1/4" O.D. copper)
• Drain line (1/2" I.D. hose)
• Low voltage wire
• Bypass ductwork
Return
• Model 50 current sensing relay
(if required)
Supply
UPFLOW
Supply
Supply
Drain Line
Floor Drain or
Condensate
Pump
12
Return
4
5
Drain Line
3
6
Supply
Supply
Drain Line
Floor Drain or
Condensate
Pump
HORIZONTAL
Return
Floor Drain or
Condensate
Drain Line
Pump
90-1079
1
11
90-1250